Red blood cells(RBCs)are the most abundant human blood cells.RBC aggregation and deformation strongly determine blood viscosity which impacts hemorheology and microcirculation.In turn,RBC properties depend on di®...Red blood cells(RBCs)are the most abundant human blood cells.RBC aggregation and deformation strongly determine blood viscosity which impacts hemorheology and microcirculation.In turn,RBC properties depend on di®erent endogenous and exogenous factors.One such factor is nitric oxide(NO),which is mainly produced by endothelial cells(EC)from L-arginine amino acid in the circulatory system.Since the mechanisms of the RBC-endothelium interplay are not clear up to date and considering its possible clinical importance,the aims of this study are to investigate in vitro:(1)The effect of L-arginine induced NO on RBC aggregation and adhesion to endothelium;(2)the NO e®ect on RBC aggregation and deformation induced by L-arginine and sodium nitroprusside without the presence of endothelium in the samples.The RBC aggregation and adhesion to a monolayer of EC were studied using optical tweezers(OT).The RBC deformability and aggregation without endothelium in the samples were studied using the flow chamber method and Myrenne aggregometer.We confirmed that NO increases deformability and decreases aggregation of RBCs.We showed that the soluble guanylate cyclase pathway appears to be the only NO signaling pathway involved.In the samples with the endothelium,the "bell-shaped"dependence of RBC aggregation force on L-arginine concentration was observed,which improves our knowledge about the process of NO production by endothelium.Additionally,data related to L-arginine accumulation by endothelium were obtained:Necessity of the presence of extracellular L-arginine stated by other authors was put under question.In our study,NO decreased the RBC-endothelium adhesion,however,the tendency appeared to be weak and was not confirmed in another set of experiments.To our knowledge,this is the first attempt to measure the forces of RBC adhesion to endothelium monolayer with OT.展开更多
Due to its toxicity, dichlorvos—a common organophosphate pesticide—poses significant risks to human health. This study utilized male Wistar rats to explore the potential protective effects of L-arginine supplementat...Due to its toxicity, dichlorvos—a common organophosphate pesticide—poses significant risks to human health. This study utilized male Wistar rats to explore the potential protective effects of L-arginine supplementation against dichlorvos-induced toxicity, focusing on cardiotoxicity, haematotoxicity and oxidative stress. The rats were divided into four groups: Control, L-arginine (L), Dichlorvos (D), and L-arginine + Dichlorvos (L + D). Dichlorvos was administered to the D group, L-arginine (100 mg/kg) to the L group, and both L-arginine and dichlorvos to the L + D group. The study evaluated various parameters, including cardiovascular, oxidative stress markers, and haematological indices. Significant changes in haematological parameters such as haemoglobin (Hb), haematocrit (HCT), and red blood cell count (RBC) indicated haematotoxicity after dichlorvos administration. Additionally, elevated cardiac markers, including lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB), suggested cardiotoxic effects. Exposure to dichlorvos also resulted in decreased antioxidant enzyme levels and increased oxidative stress indicators like malondialdehyde (MDA). Remarkably, L-arginine supplementation mitigated the damage caused by dichlorvos. It normalized the altered haematological parameters, demonstrating its protective effect against haematotoxicity. The rise in cardiac markers was reduced with L-arginine supplementation, indicating protection against cardiotoxicity. Moreover, L-arginine significantly decreased oxidative stress, as evidenced by lower MDA levels and restored antioxidant enzyme activity. In conclusion, L-arginine supplementation in male Wistar rats showed promising protective effects against dichlorvos-induced cardiotoxicity, haematotoxicity and oxidative stress. This suggests that L-arginine may offer a beneficial intervention to mitigate the adverse effects of dichlorvos on blood and heart health, paving the way for potential treatments for pesticide poisoning.展开更多
The Janus fabrics designed for personal moisture/thermal regulation have garnered significant attention for their potential to enhance human comfort.However,the development of smart and dynamic fabrics capable of mana...The Janus fabrics designed for personal moisture/thermal regulation have garnered significant attention for their potential to enhance human comfort.However,the development of smart and dynamic fabrics capable of managing personal moisture/thermal comfort in response to changing external environments remains a challenge.Herein,a smart cellulose-based Janus fabric was designed to dynamically manage personal moisture/heat.The cotton fabric was grafted with N-isopropylacrylamide to construct a temperature-stimulated transport channel.Subsequently,hydrophobic ethyl cellulose and hydrophilic cellulose nanofiber were sprayed on the bottom and top sides of the fabric to obtain wettability gradient.The fabric exhibits anti-gravity directional liquid transportation from hydrophobic side to hydrophilic side,and can dynamically and continuously control the transportation time in a wide range of 3–66 s as the temperature increases from 10 to 40℃.This smart fabric can quickly dissipate heat at high temperatures,while at low temperatures,it can slow down the heat dissipation rate and prevent the human from becoming too cold.In addition,the fabric has UV shielding and photodynamic antibacterial properties through depositing graphitic carbon nitride nanosheets on the hydrophilic side.This smart fabric offers an innovative approach to maximizing personal comfort in environments with significant temperature variations.展开更多
The conventional perception of astrocytes as mere supportive cells within the brain has recently been called into question by empirical evidence, which has revealed their active involvement in regulating brain functio...The conventional perception of astrocytes as mere supportive cells within the brain has recently been called into question by empirical evidence, which has revealed their active involvement in regulating brain function and encoding behaviors associated with emotions.Specifically, astrocytes in the basolateral amygdala have been found to play a role in the modulation of anxiety-like behaviors triggered by chronic stress. Nevertheless, the precise molecular mechanisms by which basolateral amygdala astrocytes regulate chronic stress–induced anxiety-like behaviors remain to be fully elucidated. In this study, we found that in a mouse model of anxiety triggered by unpredictable chronic mild stress, the expression of excitatory amino acid transporter 2 was upregulated in the basolateral amygdala. Interestingly, our findings indicate that the targeted knockdown of excitatory amino acid transporter 2 specifically within the basolateral amygdala astrocytes was able to rescue the anxiety-like behavior in mice subjected to stress. Furthermore, we found that the overexpression of excitatory amino acid transporter 2 in the basolateral amygdala, whether achieved through intracranial administration of excitatory amino acid transporter 2agonists or through injection of excitatory amino acid transporter 2-overexpressing viruses with GfaABC1D promoters, evoked anxiety-like behavior in mice. Our single-nucleus RNA sequencing analysis further confirmed that chronic stress induced an upregulation of excitatory amino acid transporter 2 specifically in astrocytes in the basolateral amygdala. Moreover, through in vivo calcium signal recordings, we found that the frequency of calcium activity in the basolateral amygdala of mice subjected to chronic stress was higher compared with normal mice.After knocking down the expression of excitatory amino acid transporter 2 in the basolateral amygdala, the frequency of calcium activity was not significantly increased, and anxiety-like behavior was obviously mitigated. Additionally, administration of an excitatory amino acid transporter 2 inhibitor in the basolateral amygdala yielded a notable reduction in anxiety level among mice subjected to stress. These results suggest that basolateral amygdala astrocytic excitatory amino acid transporter 2 plays a role in in the regulation of unpredictable chronic mild stress-induced anxiety-like behavior by impacting the activity of local glutamatergic neurons, and targeting excitatory amino acid transporter 2 in the basolateral amygdala holds therapeutic promise for addressing anxiety disorders.展开更多
In addition to the loss of motor function,~60% of patients develop pain after spinal cord injury.The cellular-molecular mechanisms are not well understood,but the data suggests that plasticity within the rostral,epice...In addition to the loss of motor function,~60% of patients develop pain after spinal cord injury.The cellular-molecular mechanisms are not well understood,but the data suggests that plasticity within the rostral,epicenter,and caudal penumbra of the injury site initiates a cellularmolecular interplay that acts as a rewiring mechanism leading to central neuropathic pain.Sprouting can lead to the formation of new connections triggering abnormal sensory transmission.The excitatory glutamate transporters are responsible for the reuptake of extracellular glutamate which makes them a critical target to prevent neuronal hyperexcitability and excitotoxicity.Our previous studies showed a sexually dimorphic therapeutic window for spinal cord injury after treatment with the selective estrogen receptor modulator tamoxifen.In this study,we investigated the anti-allodynic effects of tamoxifen in male and female rats with spinal cord injury.We hypothesized that tamoxifen exerts anti-allodynic effects by increasing the expression of glutamate transporters,leading to reduced hyperexcitability of the secondary neuron or by decreasing aberrant sprouting.Male and female rats received a moderate contusion to the thoracic spinal cord followed by subcutaneous slow-release treatment of tamoxifen or matrix pellets as a control(placebo).We used von Frey monofilaments and the“up-down method”to evaluate mechanical allodynia.Tamoxifen treatment decreased allodynia only in female rats with spinal cord injury revealing a sexdependent effect.The expression profile of glutamatergic transporters(excitatory amino acid transporter 1/glutamate aspartate transporter and excitatory amino acid transporter 2/glutamate transporter-1)revealed a sexual dimorphism in the rostral,epicenter,and caudal areas of the spinal cord with a pattern of expression primarily on astrocytes.Female rodents showed a significantly higher level of excitatory amino acid transporter-1 expression while male rodents showed increased excitatory amino acid transporter-2 expression compared with female rodents.Analyses of peptidergic(calcitonin gene-related peptide-α)and non-peptidergic(isolectin B4)fibers outgrowth in the dorsal horn after spinal cord injury showed an increased calcitonin gene-related peptide-α/isolectin B4 ratio in comparison with sham,suggesting increased receptive fields in the dorsal horn.Although the behavioral assay shows decreased allodynia in tamoxifen-treated female rats,this was not associated with overexpression of glutamate transporters or alterations in the dorsal horn laminae fibers at 28 days post-injury.Our findings provide new evidence of the sexually dimorphic expression of glutamate transporters in the spinal cord.The dimorphic expression revealed in this study provides a therapeutic opportunity for treating chronic pain,an area with a critical need for treatment.展开更多
Aim L-Arginine· L-aspartate, a double salt, has been recently reported toinhibit platelet aggregation and thrombosis, but its action mechanism is not clear yet. This studywas conducted to investigate its effect o...Aim L-Arginine· L-aspartate, a double salt, has been recently reported toinhibit platelet aggregation and thrombosis, but its action mechanism is not clear yet. This studywas conducted to investigate its effect on FITC-PAC-1, an anti-glycoprotein IIb/IIIa monoclonalantibody binding to activated platelets, and on correlative autacoid levels in plasma or inplatelets in order to explore its potential pathway of inhibiting platelet aggregation andthrombosis. Methods Monoclonal antibody binding to activated platelets was assayed by flowcytometry; NO was assessed by colorimetric method. cAMP, TXB_2 or 6-keto-PGF_(1α) levels wereassessed by radioimmunoassay. Results Gavaged 30 mg·kg^(-1) of L-arginine·L-aspartate increasedboth concentration of NO in plasma and 6-keto-PGF_(1) in incubated supernatant of aortic segment ofrats ex vivo (P < 0.05), but it did not influence cAMP content in platelets and the level of TXB_2or 6-keto-PGF_(1) in plasma of rats, whereas ASA significantly lowered TXB_2 or 6-keto-PGF_(1α) inplasma. Both 100 μmol-L^(-1) of L-arginine ·L-aspartate and ASA inhibited FITC-PAC-1 binding toactivated platelets in vitro. Conclusion The increase in NO and PGI_2 release from endo-thelialcells and consequent inhibition of platelet activation may contribute to the inhibition of plateletaggregation and thrombosis by L-arginine· L-aspartate; whereas arachidonic acid or cAMP metabolicpathway is not closely correlative with the studied effect.展开更多
AIM： To discuss the changes of intestinal mucosal immune function in rats with experimental severe acute pancreatitis （SAP） and the regulatory effect of L-arginine. METHODS： Male adult Wistar rats were randomly di...AIM： To discuss the changes of intestinal mucosal immune function in rats with experimental severe acute pancreatitis （SAP） and the regulatory effect of L-arginine. METHODS： Male adult Wistar rats were randomly divided into pancreatitis group, sham-operation group, and L-arginine treatment group. Animals were killed at 24, 48, and 72 h after SAP models were developed and specimens were harvested. Endotoxin concentration in portal vein was determined by limulus endotoxin analysis kit. CD3＋, CD4＋, CD8＋ T lymphoo/tes in intestinal mucosal lamina propria were examined by immunohistochemistry. Secretory immunoglobulin A （SIgA） in cecum feces was examined by radioimmunoassay. RESULTS： Compared to the control group, plasma endotoxin concentration in the portal vein increased, percentage of CD3＋ and CD4＋ T lymphocyte subsets in the end of intestinal mucosal lamina propria reduced significantly, CD4＋/CD8＋ ratio decreased, and SIgA concentrations in cecum feces reduced at 24, 48, and 72 h after SAP developed. Compared to SAP group, the L-arginine treatment group had a lower level of plasma endotoxin concentration in the portal vein, a higher CD3＋ and CD4＋ T lymphocyte percentage in the end of intestinal mucosal lamina propria, an increased ratio of CD4＋/CD8＋ and a higher SIgA concentration in cecum feces. CONCLUSION： Intestinal immune suppression occurs in the early stage of SAP rats, which may be the main reason for bacterial and endotoxin translocation. L-arginine can improve the intestinal immunity and reduce bacterial and endotoxin translocation in SAP rats.展开更多
Under the catalysis of dioxygenase L-arginine is converted to L-citrulline and nitric oxide,the latter exhibits endothelium derived relaxing factor(EDRF)-like actions.N^G-nitro-L-arginine has an inhibitory effect on t...Under the catalysis of dioxygenase L-arginine is converted to L-citrulline and nitric oxide,the latter exhibits endothelium derived relaxing factor(EDRF)-like actions.N^G-nitro-L-arginine has an inhibitory effect on the biosynthesis of EDRF in vitro and in vivo,hence it is an EDRF antagonist.The results of the present work indicate that both N^G-NO_2-L-Arg-OH and HCl·N^G-NO_2-L- Arg-OCH_3 have vasodilating effect in vitro,but produced dose-depending increase in mean arterial blood pressure(MAP)in vivo.In vitro HCl·N_G-NO_2-L-Arg-N_G-NO_2-L-Arg-OCH_3 relaxed rat aortic strip pretreated with noradrenaline(NE).In vivo,however,it produced biphasic effect,i.e,decreased MAP at lower dose and increases MAP at higher dose, N_G-Tos-L-Arg-N_G-Tos-L-Arg-OH produced dose-depending vasodilating and hypotensive actions.展开更多
AIM: Small intestinal ischemia-reperfusion (IR) has been demonstrated to result in both local mucosal injury and systemic injuries. The exact role of nitric oxide (NO) in intestinal IR is unclear. We propose that NO a...AIM: Small intestinal ischemia-reperfusion (IR) has been demonstrated to result in both local mucosal injury and systemic injuries. The exact role of nitric oxide (NO) in intestinal IR is unclear. We propose that NO and some other cytokines change in the reperfusion period and these changes are associated with lung injury. The aim of this study was to determine the effect of supplementing NO substrate, L-arginine (L-arg), on serum and pulmonary cytokine production during small intestinal IR in immature rats. METHODS: Immature rats underwent 60 min. of superior mesenteric artery occlusion followed by 90 min of reperfusion. L-arg (250 mg/kg) was given intravenously to the experimental group (IR+L-arg) which received L-arg after 45 min of intestinal ischemia. Serum and lung endothelin-1 (ET-1), NO, malondialdehyde (MDA), and tumor necrosis factor a (TNFα) were measured. Sham operation (SHAM) and intestinal IR (IR) groups were performed as control. The lavage fluid of the lung was collected by bronchoalveolar lavage (BAL) and white blood cells and polymorphonuclear cells (PMNs) were immediately counted to identify lung damage. RESULTS: When L-arg was given during small intestinal IR, serum NO concentration increased significantly in IR+L-arg group (162.17±42.93 μmol/L) when compared with IR group (87.57±23.17 μmol/L, t=3.190, P= 0.008 <0.01). Serum MDA reduced significantly in IR+L-arg group (8.93±1.50 nmol/L) when compared with SHAM (23.78±7.81 nmol/L, t= 3.243, P= 0.007<0.01) and IR (25.54±9.32 nmol/L, t= 3.421, P= 0.006<0.01). ET-1 level in lung tissues was significantly lower in IR+L-arg group (13.81±7.84 pg/mL) than that in SHAM (35.52±10.82 pg/mL, t= 2,571, P= 0,03<0.05) and IR (50.83±22.05 pg/mL, t= 3.025, P= 0.009<0.01) groups. MDA contents in lung tissues were significantly lower in IR+L-arg group (10.73±1.99 nmol/L) than in SHAM (16.62±2.28 nmol/L, t= 3.280, P = 0.007<0.01) and IR (21.90±4.82 nmol/L, t= 3.322, P= 0.007<0.01) groups. Serum and lung TNFα concentrations were not significantly different in three groups. NO contents in lung homogenates and white blood cell counts in BAL had no significant difference in three groups; but the percentage of PMNs in BAL was 13.50±8.92, 33.20±16.59, and 22.50±6.09 in SHAM, IR, and IR+L-arg groups, respectively. CONCLUSION: Small intestinal IR induced increases of pulmonary neutrophil infiltration in immature rats. Neutrophil infiltration in lung tissues was reduced by L-arg administration but remained higher than in SHAM group. L-arg administration during intestinal IR enhances serum NO production, reduces serum MDA and lung ET-1 and MDA levels, resulting in the improvement of systemic endothelial function. L-arg supplementation before reperfusion may act as a useful clinical adjunct in the management of intestinal IR, thus preventing the development of adult respiratory distress syndrome, even multiple organ dysfunction syndrome (MODS).展开更多
BACKGROUND: Post-transplantation pancreatitis andgraft thrombosis are two major complications of pancreastrans-plantation that contribute to morbidity, mortality, andgraft loss. Nitric oxide (NO) is a potent vasodilat...BACKGROUND: Post-transplantation pancreatitis andgraft thrombosis are two major complications of pancreastrans-plantation that contribute to morbidity, mortality, andgraft loss. Nitric oxide (NO) is a potent vasodilator agentformed when L-arginine ( L-Arg) is converted to L-citrul-line by the action of NO synthase (NOS), and plays a ma-jor role in microcirculatory changes. We therefore investi-gated the effect of L-Arg on reperfusion injury followingpancreaticoduodenal transplantation in rats.METHODS: The homologous male Wistar rat model ofheterotopic total pancreaticoduodenal transplantation wasused. The L-Arg-treated rats received the intravenous in-jection of L-Arg 5 minutes before and after reperfusion at adose of 200 mg/kg while the N-Nitro-L-arginine methyl es-ter (L-NAME) -treated rats at a dose of 10 mg/kg. Theamount of NO in the pancreas graft was measured. Serumconcentration of cytokine-induced neutrophil chemoattrac-tant ( CINC) was determined by enzyme-linked immu-nosorbant assay, the expression of CINC mRNA was detect-ed by Northern blot assay in the pancreas graft, and the ac-tivity of myeloperoxidase (MPO) was measured. Histolo-gical examination was performed.RESULTS: The amount of NO was higher in the L-Arggroup than in the control group, while it was lower in theL-NAME group than in the control group (P <0.05). Thepeak of serum CINC concentration occurred 3 hours afterreperfusion with the difference among the groups being sig-nificant. The expression peak of CINC mRNA in the pan-creas graft occurred 3 hours after reperfusion. The expres-sion level in the L-Arg group (7.66 ± 1.53 μg/L) was lowerthan in the control group (26.31±2.01 μg/L), while in theL-NAME group (34.18 ±3.12 μg/L) it was higher than thatin the control group (P <0. 05). The activity of MPO inthe L-Arg group was obviously decreasd as compared within the other groups. The pancreas inflammation was ame-liorated when L-Arg was administered, whereas the panc-reas damage was aggravated when L-NAME was adminis-tered.CONCLUSIONS: L-Arg can increase the amount of NOand inhibit the elevation of CINC, the CINC mRNA ex-pression and early neutrophil accumulation in the pancreas.NO has protective effects on ischemia/reperfusion injury inpancreaticoduodenal transplantation.展开更多
Background:Prenatal nutrition is crucial for embryonic development and neonatal growth,and has the potential to be a main determinant of life-long health.In the present study,we used a layer chick model to investigate...Background:Prenatal nutrition is crucial for embryonic development and neonatal growth,and has the potential to be a main determinant of life-long health.In the present study,we used a layer chick model to investigate the effects of in ovo feeding(IOF)of L-arginine(Arg)on growth,intestinal development,intestinal microbiota and metabolism.The treatments included the non-injected control,saline-injected control,and saline containing 2,6,or 10 mg Arg groups.Results:IOF Arg increased early intestinal index and villus height,and enhanced uptake of residual yolk lipid,contributing to subsequent improvement in the early growth performance of chicks.Prenatal Arg supplementation also increased the early microbialα-diversity,the relative abundance of Lactobacillales and Clostridiales,and decreased the relative abundance of Proteobacteria of cecum in chicks.Furthermore,the shift of cecal microbiota composition and the colonization of potential probiotics were accelerated by IOF of Arg.Simultaneously,metabolomics showed that metabolisms of galactose,taurine-conjugated bile acids and lipids were modulated to direct more energy and nutrients towards rapid growth of intestine at the beginning of post-hatch when embryos received IOF of Arg.Conclusions:Prenatal Arg supplementation showed beneficial effects on the early intestinal development,cecal microbiota and host metabolism of layer chicks,contributing to subsequent improvement in the early growth performance.These findings provide new insight into the role of IOF of Arg in the establishment of the gut microbiota of newly-hatched layer chicks,and can expand our fundamental knowledge about prenatal nutrition,early bacterial colonization and intestinal development in neonate.展开更多
Exhaled breath nitric oxide （NO） is an accepted asthma biomarker. Lung concentrations of NO and its amino acid precursor, L-arginine, are regulated by the relative expressions of the NO synthase （NOS） and arginase...Exhaled breath nitric oxide （NO） is an accepted asthma biomarker. Lung concentrations of NO and its amino acid precursor, L-arginine, are regulated by the relative expressions of the NO synthase （NOS） and arginase isoforms. Increased expression of arginase I and NOS2 occurs in murine models of allergic asthma and in biopsies of asthmatic airways. Although clinical trials involving the inhibition of NO-producing enzymes have shown mixed results, small molecule arginase inhibitors have shown potential as a therapeutic intervention in animal and cell culture models. Their transition to clinical trials is hampered by concerns regarding their safety and potential tox- icity. In this review, we discuss the paradigm of arginase and NOS competition for their substrate L-arginine in the asthmatic airway. We address the functional role of L-arginine in inflammation and the potential role of arginase inhibitors as therapeutics.展开更多
Objective In Corynebacterium crenatum,the adjacent D311 and D312 of N-acetyl-L-glutamate kinase(NAGK),as a key rate-limiting enzyme of L-arginine biosynthesis under substrate regulatory control by arginine,were initia...Objective In Corynebacterium crenatum,the adjacent D311 and D312 of N-acetyl-L-glutamate kinase(NAGK),as a key rate-limiting enzyme of L-arginine biosynthesis under substrate regulatory control by arginine,were initially replaced with two arginine residues to investigate the L-arginine feedback inhibition for NAGK.Methods NAGK enzyme expression was evaluated using a plasmid-based method.Homologous recombination was employed to eliminate the pro B.Results The IC50 and enzyme activity of NAGK M4,in which the D311 R and D312 R amino acid substitutions were combined with the previously reported E19 R and H26 E substitutions,were 3.7-fold and 14.6% higher,respectively,than those of the wild-type NAGK.NAGK M4 was successfully introduced into the C.crenatum MT genome without any genetic markers;the L-arginine yield of C.crenatum MT-M4 was 26.2% higher than that of C.crenatum MT.To further improve upon the L-arginine yield,we constructed the mutant C.crenatum MT-M4 ?pro B.The optimum concentration of L-proline was also investigated in order to determine its contribution to L-arginine yield.After L-proline was added to the medium at 10 mmol/L,the L-arginine yield reached 16.5 g/L after 108 h of shake-flask fermentation,approximately 70.1% higher than the yield attained using C.crenatum MT.Conclusion Feedback inhibition of L-arginine on NAGK in C.crenatum is clearly alleviated by the M4 mutation of NAGK,and deletion of the pro B in C.crenatum from MT to M4 results in a significant increase in arginine production.展开更多
基金supported by the Russian Science Foundation Grant No.22-15-00120.
文摘Red blood cells(RBCs)are the most abundant human blood cells.RBC aggregation and deformation strongly determine blood viscosity which impacts hemorheology and microcirculation.In turn,RBC properties depend on di®erent endogenous and exogenous factors.One such factor is nitric oxide(NO),which is mainly produced by endothelial cells(EC)from L-arginine amino acid in the circulatory system.Since the mechanisms of the RBC-endothelium interplay are not clear up to date and considering its possible clinical importance,the aims of this study are to investigate in vitro:(1)The effect of L-arginine induced NO on RBC aggregation and adhesion to endothelium;(2)the NO e®ect on RBC aggregation and deformation induced by L-arginine and sodium nitroprusside without the presence of endothelium in the samples.The RBC aggregation and adhesion to a monolayer of EC were studied using optical tweezers(OT).The RBC deformability and aggregation without endothelium in the samples were studied using the flow chamber method and Myrenne aggregometer.We confirmed that NO increases deformability and decreases aggregation of RBCs.We showed that the soluble guanylate cyclase pathway appears to be the only NO signaling pathway involved.In the samples with the endothelium,the "bell-shaped"dependence of RBC aggregation force on L-arginine concentration was observed,which improves our knowledge about the process of NO production by endothelium.Additionally,data related to L-arginine accumulation by endothelium were obtained:Necessity of the presence of extracellular L-arginine stated by other authors was put under question.In our study,NO decreased the RBC-endothelium adhesion,however,the tendency appeared to be weak and was not confirmed in another set of experiments.To our knowledge,this is the first attempt to measure the forces of RBC adhesion to endothelium monolayer with OT.
文摘Due to its toxicity, dichlorvos—a common organophosphate pesticide—poses significant risks to human health. This study utilized male Wistar rats to explore the potential protective effects of L-arginine supplementation against dichlorvos-induced toxicity, focusing on cardiotoxicity, haematotoxicity and oxidative stress. The rats were divided into four groups: Control, L-arginine (L), Dichlorvos (D), and L-arginine + Dichlorvos (L + D). Dichlorvos was administered to the D group, L-arginine (100 mg/kg) to the L group, and both L-arginine and dichlorvos to the L + D group. The study evaluated various parameters, including cardiovascular, oxidative stress markers, and haematological indices. Significant changes in haematological parameters such as haemoglobin (Hb), haematocrit (HCT), and red blood cell count (RBC) indicated haematotoxicity after dichlorvos administration. Additionally, elevated cardiac markers, including lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB), suggested cardiotoxic effects. Exposure to dichlorvos also resulted in decreased antioxidant enzyme levels and increased oxidative stress indicators like malondialdehyde (MDA). Remarkably, L-arginine supplementation mitigated the damage caused by dichlorvos. It normalized the altered haematological parameters, demonstrating its protective effect against haematotoxicity. The rise in cardiac markers was reduced with L-arginine supplementation, indicating protection against cardiotoxicity. Moreover, L-arginine significantly decreased oxidative stress, as evidenced by lower MDA levels and restored antioxidant enzyme activity. In conclusion, L-arginine supplementation in male Wistar rats showed promising protective effects against dichlorvos-induced cardiotoxicity, haematotoxicity and oxidative stress. This suggests that L-arginine may offer a beneficial intervention to mitigate the adverse effects of dichlorvos on blood and heart health, paving the way for potential treatments for pesticide poisoning.
基金support of this work by National Key Research and Development Program of China(2019YFC19059003)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(23KJB430024)+1 种基金Jiangsu Funding Program for Excellent Postdoctoral Talent(2023ZB680)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)are gratefully acknowledged.
文摘The Janus fabrics designed for personal moisture/thermal regulation have garnered significant attention for their potential to enhance human comfort.However,the development of smart and dynamic fabrics capable of managing personal moisture/thermal comfort in response to changing external environments remains a challenge.Herein,a smart cellulose-based Janus fabric was designed to dynamically manage personal moisture/heat.The cotton fabric was grafted with N-isopropylacrylamide to construct a temperature-stimulated transport channel.Subsequently,hydrophobic ethyl cellulose and hydrophilic cellulose nanofiber were sprayed on the bottom and top sides of the fabric to obtain wettability gradient.The fabric exhibits anti-gravity directional liquid transportation from hydrophobic side to hydrophilic side,and can dynamically and continuously control the transportation time in a wide range of 3–66 s as the temperature increases from 10 to 40℃.This smart fabric can quickly dissipate heat at high temperatures,while at low temperatures,it can slow down the heat dissipation rate and prevent the human from becoming too cold.In addition,the fabric has UV shielding and photodynamic antibacterial properties through depositing graphitic carbon nitride nanosheets on the hydrophilic side.This smart fabric offers an innovative approach to maximizing personal comfort in environments with significant temperature variations.
基金supported by the National Natural Science Foundation of China,Nos.32371070 (to JT),31761163005 (to JT),32100824 (to QX)the Shenzhen Science and Technology Program,Nos.RCBS20210609104606024 (to QX),JCY20210324101813035 (to DL)+4 种基金the Guangdong Provincial Key S&T Program,No.2018B030336001 (to JT)the Key Basic Research Program of Shenzhen Science and Technology Innovation Commission,Nos.JCYJ20200109115405930 (to JT),JCYJ20220818101615033 (to DL),JCYJ20210324115811031 (to QX),JCYJ20200109150717745 (to QX)Shenzhen Key Laboratory of Neuroimmunomodulation for Neurological Diseases,No.ZDSYS20220304163558001 (to JT)Guangdong Provincial Key Laboratory of Brain Connectome and Behavior,No.2023B1212060055 (to JT)the China Postdoctoral Science Foundation,No.2021M693298 (to QX)。
文摘The conventional perception of astrocytes as mere supportive cells within the brain has recently been called into question by empirical evidence, which has revealed their active involvement in regulating brain function and encoding behaviors associated with emotions.Specifically, astrocytes in the basolateral amygdala have been found to play a role in the modulation of anxiety-like behaviors triggered by chronic stress. Nevertheless, the precise molecular mechanisms by which basolateral amygdala astrocytes regulate chronic stress–induced anxiety-like behaviors remain to be fully elucidated. In this study, we found that in a mouse model of anxiety triggered by unpredictable chronic mild stress, the expression of excitatory amino acid transporter 2 was upregulated in the basolateral amygdala. Interestingly, our findings indicate that the targeted knockdown of excitatory amino acid transporter 2 specifically within the basolateral amygdala astrocytes was able to rescue the anxiety-like behavior in mice subjected to stress. Furthermore, we found that the overexpression of excitatory amino acid transporter 2 in the basolateral amygdala, whether achieved through intracranial administration of excitatory amino acid transporter 2agonists or through injection of excitatory amino acid transporter 2-overexpressing viruses with GfaABC1D promoters, evoked anxiety-like behavior in mice. Our single-nucleus RNA sequencing analysis further confirmed that chronic stress induced an upregulation of excitatory amino acid transporter 2 specifically in astrocytes in the basolateral amygdala. Moreover, through in vivo calcium signal recordings, we found that the frequency of calcium activity in the basolateral amygdala of mice subjected to chronic stress was higher compared with normal mice.After knocking down the expression of excitatory amino acid transporter 2 in the basolateral amygdala, the frequency of calcium activity was not significantly increased, and anxiety-like behavior was obviously mitigated. Additionally, administration of an excitatory amino acid transporter 2 inhibitor in the basolateral amygdala yielded a notable reduction in anxiety level among mice subjected to stress. These results suggest that basolateral amygdala astrocytic excitatory amino acid transporter 2 plays a role in in the regulation of unpredictable chronic mild stress-induced anxiety-like behavior by impacting the activity of local glutamatergic neurons, and targeting excitatory amino acid transporter 2 in the basolateral amygdala holds therapeutic promise for addressing anxiety disorders.
基金supported by COBRE(P30GM149367)the Puerto Rico Science&Technology Trust(2022-00125)+1 种基金MBRS-RISE Program(R25 GM061838)SC1GM144032 program(all to JDM)。
文摘In addition to the loss of motor function,~60% of patients develop pain after spinal cord injury.The cellular-molecular mechanisms are not well understood,but the data suggests that plasticity within the rostral,epicenter,and caudal penumbra of the injury site initiates a cellularmolecular interplay that acts as a rewiring mechanism leading to central neuropathic pain.Sprouting can lead to the formation of new connections triggering abnormal sensory transmission.The excitatory glutamate transporters are responsible for the reuptake of extracellular glutamate which makes them a critical target to prevent neuronal hyperexcitability and excitotoxicity.Our previous studies showed a sexually dimorphic therapeutic window for spinal cord injury after treatment with the selective estrogen receptor modulator tamoxifen.In this study,we investigated the anti-allodynic effects of tamoxifen in male and female rats with spinal cord injury.We hypothesized that tamoxifen exerts anti-allodynic effects by increasing the expression of glutamate transporters,leading to reduced hyperexcitability of the secondary neuron or by decreasing aberrant sprouting.Male and female rats received a moderate contusion to the thoracic spinal cord followed by subcutaneous slow-release treatment of tamoxifen or matrix pellets as a control(placebo).We used von Frey monofilaments and the“up-down method”to evaluate mechanical allodynia.Tamoxifen treatment decreased allodynia only in female rats with spinal cord injury revealing a sexdependent effect.The expression profile of glutamatergic transporters(excitatory amino acid transporter 1/glutamate aspartate transporter and excitatory amino acid transporter 2/glutamate transporter-1)revealed a sexual dimorphism in the rostral,epicenter,and caudal areas of the spinal cord with a pattern of expression primarily on astrocytes.Female rodents showed a significantly higher level of excitatory amino acid transporter-1 expression while male rodents showed increased excitatory amino acid transporter-2 expression compared with female rodents.Analyses of peptidergic(calcitonin gene-related peptide-α)and non-peptidergic(isolectin B4)fibers outgrowth in the dorsal horn after spinal cord injury showed an increased calcitonin gene-related peptide-α/isolectin B4 ratio in comparison with sham,suggesting increased receptive fields in the dorsal horn.Although the behavioral assay shows decreased allodynia in tamoxifen-treated female rats,this was not associated with overexpression of glutamate transporters or alterations in the dorsal horn laminae fibers at 28 days post-injury.Our findings provide new evidence of the sexually dimorphic expression of glutamate transporters in the spinal cord.The dimorphic expression revealed in this study provides a therapeutic opportunity for treating chronic pain,an area with a critical need for treatment.
文摘Aim L-Arginine· L-aspartate, a double salt, has been recently reported toinhibit platelet aggregation and thrombosis, but its action mechanism is not clear yet. This studywas conducted to investigate its effect on FITC-PAC-1, an anti-glycoprotein IIb/IIIa monoclonalantibody binding to activated platelets, and on correlative autacoid levels in plasma or inplatelets in order to explore its potential pathway of inhibiting platelet aggregation andthrombosis. Methods Monoclonal antibody binding to activated platelets was assayed by flowcytometry; NO was assessed by colorimetric method. cAMP, TXB_2 or 6-keto-PGF_(1α) levels wereassessed by radioimmunoassay. Results Gavaged 30 mg·kg^(-1) of L-arginine·L-aspartate increasedboth concentration of NO in plasma and 6-keto-PGF_(1) in incubated supernatant of aortic segment ofrats ex vivo (P < 0.05), but it did not influence cAMP content in platelets and the level of TXB_2or 6-keto-PGF_(1) in plasma of rats, whereas ASA significantly lowered TXB_2 or 6-keto-PGF_(1α) inplasma. Both 100 μmol-L^(-1) of L-arginine ·L-aspartate and ASA inhibited FITC-PAC-1 binding toactivated platelets in vitro. Conclusion The increase in NO and PGI_2 release from endo-thelialcells and consequent inhibition of platelet activation may contribute to the inhibition of plateletaggregation and thrombosis by L-arginine· L-aspartate; whereas arachidonic acid or cAMP metabolicpathway is not closely correlative with the studied effect.
文摘AIM： To discuss the changes of intestinal mucosal immune function in rats with experimental severe acute pancreatitis （SAP） and the regulatory effect of L-arginine. METHODS： Male adult Wistar rats were randomly divided into pancreatitis group, sham-operation group, and L-arginine treatment group. Animals were killed at 24, 48, and 72 h after SAP models were developed and specimens were harvested. Endotoxin concentration in portal vein was determined by limulus endotoxin analysis kit. CD3＋, CD4＋, CD8＋ T lymphoo/tes in intestinal mucosal lamina propria were examined by immunohistochemistry. Secretory immunoglobulin A （SIgA） in cecum feces was examined by radioimmunoassay. RESULTS： Compared to the control group, plasma endotoxin concentration in the portal vein increased, percentage of CD3＋ and CD4＋ T lymphocyte subsets in the end of intestinal mucosal lamina propria reduced significantly, CD4＋/CD8＋ ratio decreased, and SIgA concentrations in cecum feces reduced at 24, 48, and 72 h after SAP developed. Compared to SAP group, the L-arginine treatment group had a lower level of plasma endotoxin concentration in the portal vein, a higher CD3＋ and CD4＋ T lymphocyte percentage in the end of intestinal mucosal lamina propria, an increased ratio of CD4＋/CD8＋ and a higher SIgA concentration in cecum feces. CONCLUSION： Intestinal immune suppression occurs in the early stage of SAP rats, which may be the main reason for bacterial and endotoxin translocation. L-arginine can improve the intestinal immunity and reduce bacterial and endotoxin translocation in SAP rats.
基金This project was supported by the Natural Sciences Foundation of Beijing.
文摘Under the catalysis of dioxygenase L-arginine is converted to L-citrulline and nitric oxide,the latter exhibits endothelium derived relaxing factor(EDRF)-like actions.N^G-nitro-L-arginine has an inhibitory effect on the biosynthesis of EDRF in vitro and in vivo,hence it is an EDRF antagonist.The results of the present work indicate that both N^G-NO_2-L-Arg-OH and HCl·N^G-NO_2-L- Arg-OCH_3 have vasodilating effect in vitro,but produced dose-depending increase in mean arterial blood pressure(MAP)in vivo.In vitro HCl·N_G-NO_2-L-Arg-N_G-NO_2-L-Arg-OCH_3 relaxed rat aortic strip pretreated with noradrenaline(NE).In vivo,however,it produced biphasic effect,i.e,decreased MAP at lower dose and increases MAP at higher dose, N_G-Tos-L-Arg-N_G-Tos-L-Arg-OH produced dose-depending vasodilating and hypotensive actions.
基金Supported by The Natural Scientific Foundation of Shandong Province, No. Q99C13
文摘AIM: Small intestinal ischemia-reperfusion (IR) has been demonstrated to result in both local mucosal injury and systemic injuries. The exact role of nitric oxide (NO) in intestinal IR is unclear. We propose that NO and some other cytokines change in the reperfusion period and these changes are associated with lung injury. The aim of this study was to determine the effect of supplementing NO substrate, L-arginine (L-arg), on serum and pulmonary cytokine production during small intestinal IR in immature rats. METHODS: Immature rats underwent 60 min. of superior mesenteric artery occlusion followed by 90 min of reperfusion. L-arg (250 mg/kg) was given intravenously to the experimental group (IR+L-arg) which received L-arg after 45 min of intestinal ischemia. Serum and lung endothelin-1 (ET-1), NO, malondialdehyde (MDA), and tumor necrosis factor a (TNFα) were measured. Sham operation (SHAM) and intestinal IR (IR) groups were performed as control. The lavage fluid of the lung was collected by bronchoalveolar lavage (BAL) and white blood cells and polymorphonuclear cells (PMNs) were immediately counted to identify lung damage. RESULTS: When L-arg was given during small intestinal IR, serum NO concentration increased significantly in IR+L-arg group (162.17±42.93 μmol/L) when compared with IR group (87.57±23.17 μmol/L, t=3.190, P= 0.008 <0.01). Serum MDA reduced significantly in IR+L-arg group (8.93±1.50 nmol/L) when compared with SHAM (23.78±7.81 nmol/L, t= 3.243, P= 0.007<0.01) and IR (25.54±9.32 nmol/L, t= 3.421, P= 0.006<0.01). ET-1 level in lung tissues was significantly lower in IR+L-arg group (13.81±7.84 pg/mL) than that in SHAM (35.52±10.82 pg/mL, t= 2,571, P= 0,03<0.05) and IR (50.83±22.05 pg/mL, t= 3.025, P= 0.009<0.01) groups. MDA contents in lung tissues were significantly lower in IR+L-arg group (10.73±1.99 nmol/L) than in SHAM (16.62±2.28 nmol/L, t= 3.280, P = 0.007<0.01) and IR (21.90±4.82 nmol/L, t= 3.322, P= 0.007<0.01) groups. Serum and lung TNFα concentrations were not significantly different in three groups. NO contents in lung homogenates and white blood cell counts in BAL had no significant difference in three groups; but the percentage of PMNs in BAL was 13.50±8.92, 33.20±16.59, and 22.50±6.09 in SHAM, IR, and IR+L-arg groups, respectively. CONCLUSION: Small intestinal IR induced increases of pulmonary neutrophil infiltration in immature rats. Neutrophil infiltration in lung tissues was reduced by L-arg administration but remained higher than in SHAM group. L-arg administration during intestinal IR enhances serum NO production, reduces serum MDA and lung ET-1 and MDA levels, resulting in the improvement of systemic endothelial function. L-arg supplementation before reperfusion may act as a useful clinical adjunct in the management of intestinal IR, thus preventing the development of adult respiratory distress syndrome, even multiple organ dysfunction syndrome (MODS).
基金This study was supported by a grant from foundation of Liaoning ProvincialKey Projects ( No. 0025001 ), China.
文摘BACKGROUND: Post-transplantation pancreatitis andgraft thrombosis are two major complications of pancreastrans-plantation that contribute to morbidity, mortality, andgraft loss. Nitric oxide (NO) is a potent vasodilator agentformed when L-arginine ( L-Arg) is converted to L-citrul-line by the action of NO synthase (NOS), and plays a ma-jor role in microcirculatory changes. We therefore investi-gated the effect of L-Arg on reperfusion injury followingpancreaticoduodenal transplantation in rats.METHODS: The homologous male Wistar rat model ofheterotopic total pancreaticoduodenal transplantation wasused. The L-Arg-treated rats received the intravenous in-jection of L-Arg 5 minutes before and after reperfusion at adose of 200 mg/kg while the N-Nitro-L-arginine methyl es-ter (L-NAME) -treated rats at a dose of 10 mg/kg. Theamount of NO in the pancreas graft was measured. Serumconcentration of cytokine-induced neutrophil chemoattrac-tant ( CINC) was determined by enzyme-linked immu-nosorbant assay, the expression of CINC mRNA was detect-ed by Northern blot assay in the pancreas graft, and the ac-tivity of myeloperoxidase (MPO) was measured. Histolo-gical examination was performed.RESULTS: The amount of NO was higher in the L-Arggroup than in the control group, while it was lower in theL-NAME group than in the control group (P <0.05). Thepeak of serum CINC concentration occurred 3 hours afterreperfusion with the difference among the groups being sig-nificant. The expression peak of CINC mRNA in the pan-creas graft occurred 3 hours after reperfusion. The expres-sion level in the L-Arg group (7.66 ± 1.53 μg/L) was lowerthan in the control group (26.31±2.01 μg/L), while in theL-NAME group (34.18 ±3.12 μg/L) it was higher than thatin the control group (P <0. 05). The activity of MPO inthe L-Arg group was obviously decreasd as compared within the other groups. The pancreas inflammation was ame-liorated when L-Arg was administered, whereas the panc-reas damage was aggravated when L-NAME was adminis-tered.CONCLUSIONS: L-Arg can increase the amount of NOand inhibit the elevation of CINC, the CINC mRNA ex-pression and early neutrophil accumulation in the pancreas.NO has protective effects on ischemia/reperfusion injury inpancreaticoduodenal transplantation.
基金This study was supported by National Key R&D Program of China(2017YFD0500500)the earmarked fund for Modern Agro-industry Technology Research System(CARS-40-K12)+1 种基金Beijing Innovation Consortium of Agriculture Research System(BAIC04–2018)the Agricultural Science and Technology Innovation Program(ASTIP)of the Chinese Academy of Agricultural Sciences.
文摘Background:Prenatal nutrition is crucial for embryonic development and neonatal growth,and has the potential to be a main determinant of life-long health.In the present study,we used a layer chick model to investigate the effects of in ovo feeding(IOF)of L-arginine(Arg)on growth,intestinal development,intestinal microbiota and metabolism.The treatments included the non-injected control,saline-injected control,and saline containing 2,6,or 10 mg Arg groups.Results:IOF Arg increased early intestinal index and villus height,and enhanced uptake of residual yolk lipid,contributing to subsequent improvement in the early growth performance of chicks.Prenatal Arg supplementation also increased the early microbialα-diversity,the relative abundance of Lactobacillales and Clostridiales,and decreased the relative abundance of Proteobacteria of cecum in chicks.Furthermore,the shift of cecal microbiota composition and the colonization of potential probiotics were accelerated by IOF of Arg.Simultaneously,metabolomics showed that metabolisms of galactose,taurine-conjugated bile acids and lipids were modulated to direct more energy and nutrients towards rapid growth of intestine at the beginning of post-hatch when embryos received IOF of Arg.Conclusions:Prenatal Arg supplementation showed beneficial effects on the early intestinal development,cecal microbiota and host metabolism of layer chicks,contributing to subsequent improvement in the early growth performance.These findings provide new insight into the role of IOF of Arg in the establishment of the gut microbiota of newly-hatched layer chicks,and can expand our fundamental knowledge about prenatal nutrition,early bacterial colonization and intestinal development in neonate.
基金supported by the following grants:National Institute of Environmental Health Sciences funded training program in Environmental Health Sciences (No.T32 ES007058-33) to Jennifer M.Bratt,CTSC K12 Award (No.UL1RR024146)KL2RR024144 to Amir A.Zekithe American Asthma Foundation to Nicholas J.Kenyon.
文摘Exhaled breath nitric oxide （NO） is an accepted asthma biomarker. Lung concentrations of NO and its amino acid precursor, L-arginine, are regulated by the relative expressions of the NO synthase （NOS） and arginase isoforms. Increased expression of arginase I and NOS2 occurs in murine models of allergic asthma and in biopsies of asthmatic airways. Although clinical trials involving the inhibition of NO-producing enzymes have shown mixed results, small molecule arginase inhibitors have shown potential as a therapeutic intervention in animal and cell culture models. Their transition to clinical trials is hampered by concerns regarding their safety and potential tox- icity. In this review, we discuss the paradigm of arginase and NOS competition for their substrate L-arginine in the asthmatic airway. We address the functional role of L-arginine in inflammation and the potential role of arginase inhibitors as therapeutics.
基金supported by Natural Science Foundation of China,No.31360219 and No.30960012the Open Project Program of Key Laboratory of Functional Small Organic Molecule,Ministry of Education,Jiangxi Normal University(No.KLFS-KF-201414)
文摘Objective In Corynebacterium crenatum,the adjacent D311 and D312 of N-acetyl-L-glutamate kinase(NAGK),as a key rate-limiting enzyme of L-arginine biosynthesis under substrate regulatory control by arginine,were initially replaced with two arginine residues to investigate the L-arginine feedback inhibition for NAGK.Methods NAGK enzyme expression was evaluated using a plasmid-based method.Homologous recombination was employed to eliminate the pro B.Results The IC50 and enzyme activity of NAGK M4,in which the D311 R and D312 R amino acid substitutions were combined with the previously reported E19 R and H26 E substitutions,were 3.7-fold and 14.6% higher,respectively,than those of the wild-type NAGK.NAGK M4 was successfully introduced into the C.crenatum MT genome without any genetic markers;the L-arginine yield of C.crenatum MT-M4 was 26.2% higher than that of C.crenatum MT.To further improve upon the L-arginine yield,we constructed the mutant C.crenatum MT-M4 ?pro B.The optimum concentration of L-proline was also investigated in order to determine its contribution to L-arginine yield.After L-proline was added to the medium at 10 mmol/L,the L-arginine yield reached 16.5 g/L after 108 h of shake-flask fermentation,approximately 70.1% higher than the yield attained using C.crenatum MT.Conclusion Feedback inhibition of L-arginine on NAGK in C.crenatum is clearly alleviated by the M4 mutation of NAGK,and deletion of the pro B in C.crenatum from MT to M4 results in a significant increase in arginine production.
