Bhlhe40 protects cochlear hair cell-like HEI-OC1 cells against H_(2)O_(2) ‑triggered oxidative injury

Background:Cochlear hair cell injury is a common pathological feature of hearing loss.The basic helix-loop-helix family,member e40(Bhlhe40),a gene belonging to the basic helix-loop-helix(bHLH)family,exhibits strong transcriptional repression activity.Methods:Oxidative damage,in House Ear Institute-Organ of Corti 1(HEI-OC1)cells,was caused using hydrogen peroxide(H2O2).The Ad-Bhlhe40 particles were constructed to overexpress Bhlhe40 in HEI-OC1 cells.Various assays including cell counting kit-8(CCK-8),terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling assay(TUNEL),flow cytometry,immunofluorescence,and corresponding commercial kits were employed to investigate the impacts of Bhlhe40 on cell viability,apoptosis,oxidative stress levels,mitochondrial membrane potential and cellular senescence.Additionally,a dual-luciferase reporter assay was performed to confirm the targeting of the histone deacetylases 2(Hdac2)by Bhlhe40.Results:The results revealed that Bhlhe40 was downregulated in H_(2)O_(2)-treated HEI-OC1 cells,but its overexpression improved cell viability and mitigated H_(2)O_(2)-induced oxidative injury in HEI-OC1 cells with increase of superoxide dismutase(SOD),catalase(CAT)and glutathione peroxidase(GPx)activities and decrease of reactive oxygen species(ROS)levels.Besides,overexpression of Bhlhe40 suppressed H_(2)O_(2)-triggered cell senescence,as evidenced by the fact that the upregulation of P53,P21,and P16 in HEI-OC1 cells treated with H2O2 were all alleviated by Bhlhe40 overexpression.And we further verified that overexpression of Bhlhe40 could inhibit the expression of Hdac2,which may be related to the repression of Hdac2 transcription.Conclusion:This study suggests that Bhlhe40 plays a protective role against senescence and oxidative damage in cochlear hair cells exposed to H2O2.

Polaprezinc protects human colon cells from oxidative injury induced by hydrogen peroxide:Relevant to cytoprotective heat shock proteins

AIM： To investigate the effect of polaprezinc on cellular damage induced by hydrogen peroxide （H202） in human colon CaCo2 cells. METHODS： CaCo2 cells were treated with polaprezinc （10-100 pmol/L） for 6 h. After polaprezinc treatment, the cells were incubated with H202 （20μmol/L） for 1 h. Cell viability was measured by MTT assay. Western blot analysis for heat shock protein （HSP） 27 and HSP72 in the cells was performed. Moreover, cells were pretreated with quercetin （200 μmol/L）, an inhibitor of HSP synthesis, 2 h before polaprezinc treatment, and cell viability and the expression of HSP27 and 72 were assessed in these cells. RESULTS： Polaprezinc significantly protected CaCo2 cells from cell damage induced by H2O2, and up-regulated the expressions of HSP27 and HSP72 in the cells （10, 30 and 100 pmol/L of polaprezinc; 35.0% ± 7.7%, 58.3% ± 14.6% and 64.2% ± 8.2%, respectively. P 〈 0.01 versus polaprezinc-nontreated cells; 6.0% ± 4.4%）. Quercetin inhibited the up-regulation of HSP27 and HSP72 by polaprezinc and diminished the protective effect of polaprezinc against H2O2-caused injury in the cells. CONCLUSION： Polaprezinc is a useful therapeutic agent for treatment of colitis and its effects depend on the function of cytoprotective HSP in colon.

RNA-seq analysis of protective effect of epicatechin gallate on H_(2)O_(2)-induced oxidative injury in PC12 cells

Epicatechin gallate(ECG)is one of the polyphenolic compounds and has attracted much attention due to its various bioactivities.In this study,the neuroprotective eff ect of ECG against H_(2)O_(2)-induced oxidative injury in PC12 cells as well as the possible mechanisms were investigated.Cell viability was determined by MTT assay.The differentially expressed genes(DEGs),GO enrichment,and KEGG enrichment were analyzed to explore the mechanism of ECG against H_(2)O_(2)-induced oxidative injury by using the RNA-seq method.Finally,the change in the cell cycle was analyzed by fl ow cytometry.H_(2)O_(2)(400-1200μmol/L)inhibited the cell viability in a concentration-dependent manner.ECG(6-150μmol/L)eff ectively attenuated the H_(2)O_(2)-induced decrease in cell viability.RNA-seq analysis showed that ECG regulated 1058 coexpressed DEGs.GO enrichment analysis showed that the cellular component was the dominant group after ECG treatment.KEGG analysis showed that the cell cycle,fanconi anemia pathway,and homologous recombination were the important pathways for ECG in improving H_(2)O_(2)-induced oxidative injury and 28 coexpressed DEGs in the cell cycle pathway were summarized.Finally,cell cycle analysis also proved that ECG improved H_(2)O_(2)-induced cell cycle arrest in the G2/M phase.Our present study demonstrated that ECG attenuated H_(2)O_(2)-induced neurologic oxidative damage by multiple modulatory mechanisms at the molecular transcription level.These fi ndings provide new insights for further study of the molecular mechanism of the neuroprotection of ECG.

Apoptosis and oxidative injury of donor islets during isolation and purification

Objective To observe the changes of islet cell apoptosis and oxidation - antioxidation before transplantation,and to explore pathways of islet protection. Methods Fifteen human pancreases were perfused with Hanks solution containing collagenase,then digested and isolated.

Engineered Bacillus subtilis alleviates intestinal oxidative injury through Nrf2-Keap1 pathway in enterotoxigenic Escherichia coli(ETEC) K88-infected piglet

Engineered probiotics can serve as therapeutics based on their ability of produce recombinant immune-stimulating properties.In this study,we built the recombinant Bacillus subtilis WB800 expressing antimicrobial peptide KR32(WB800-KR32)using genetic engineering methods and investigated its protective effects of nuclear factor-E2-related factor 2(Nrf2)-Kelch-like ECH-associated protein 1(Keap1)pathway activation in intestinal oxidative disturbance induced by enterotoxigenic Escherichia coli(ETEC)K88 in weaned piglets.Twenty-eight weaned piglets were randomly distributed into four treatment groups with seven replicates fed with a basal diet.The feed of the control group(CON)was infused with normal sterilized saline;meanwhile,the ETEC,ETEC+WB800,and ETEC+WB800-KR32 groups were orally administered normal sterilized saline,5×10^(10)CFU(CFU:colony forming units)WB800,and 5×10^(10)CFU WB800-KR32,respectively,on Days 1-14 and all infused with ETEC K881×10^(10)CFU on Days 15-17.The results showed that pretreatment with WB800-KR32 attenuated ETEC-induced intestinal disturbance,improved the mucosal activity of antioxidant enzyme(catalase(CAT),superoxide dismutase(SOD),and glutathione peroxidase(GPx))and decreased the content of malondialdehyde(MDA).More importantly,WB800-KR32 downregulated genes involved in antioxidant defense(GPx and SOD1).Interestingly,WB800-KR32 upregulated the protein expression of Nrf2 and downregulated the protein expression of Keap1 in the ileum.WB800-KR32 markedly changed the richness estimators(Ace and Chao)of gut microbiota and increased the abundance of Eubacterium_rectale_ATCC_33656 in the feces.The results suggested that WB800-KR32 may alleviate ETEC-induced intestinal oxidative injury through the Nrf2-Keap1 pathway,providing a new perspective for WB800-KR32 as potential therapeutics to regulate intestinal oxidative disturbance in ETEC K88 infection.

Harpephyllum caffrum stimulates glucose uptake,abates redox imbalance and modulates purinergic and glucogenic enzyme activities in oxidative hepatic injury

Objective:To investigate the antioxidative and antidiabetic effects of Harpephyllum caffrum bark infusion as well as its effects on glucogenic and nucleotide hydrolyzing enzyme activities in FeSO4-induced oxidative stress in rat hepatic tissue.Methods:Harpephyllum caffrum infusion was prepared from dried plant materials(40 g)infused in boiling water(400 mL)for 20 min at room temperature.The antioxidative and inhibitory activities against carbohydrate digestive enzymes of the infusion were determined using established protocols.The liver tissues of rats were used for glucose uptake assay and to evaluate the infusion’s effect on endogenous antioxidant,glucogenic,and nucleotide hydrolyzing enzyme activities in FeSO4-induced hepatic injury.Results:The Harpephyllum caffrum infusion significantly reduced ferric iron(FRAP)and free radicals(OH•and DPPH)in a dose-dependent manner.It inhibitedα-amylase andα-glucosidase activities and increased glucose uptake in hepatic tissues.FeSO4 significantly decreased glutathione concentration,catalase,and superoxide dismutase activities while increasing malondialdehyde level,glycogen phosphorylase,fructose-1,6-bisphosphatase,and adenosine triphosphatase activities.However,treatment with Harpephyllum caffrum infusion reversed FeSO4-induced changes.Characterization of the infusion revealed the presence of catechol,O-pyrocatechuic acid,mequinol,maltol,and glycoside derivatives.Conclusions:The Harpephyllum caffrum infusion demonstrates antidiabetic and antioxidative potentials in in vitro models of type 2 diabetes as depicted by its ability to inhibit carbohydrate digestive enzymes,mitigate oxidative imbalance,and regulate glucogenic and nucleotide hydrolyzing enzyme activities in oxidative hepatic injury.

Zataria multiflora and its constituent,carvacrol,counteract sepsis-induced aortic and cardiac toxicity in rat:Involvement of nitric oxide and oxidative stress

Background:Zataria multiflora and carvacrol showed various pharmacological prop-erties including anti-inflammatory and anti-oxidant effects.However,up to now no studies have explored its potential benefits in ameliorating sepsis-induced aortic and cardiac injury.Thus,this study aimed to investigate the effects of Z.multiflora and carvacrol on nitric oxide(NO)and oxidative stress indicators in lipopolysaccharide(LPS)-induced aortic and cardiac injury.Methods:Adult male Wistar rats were assigned to:Control,lipopolysaccharide(LPS)(1 mg/kg,intraperitoneal(i.p.)),and Z.multiflora hydro-ethanolic extract(ZME,50–200 mg/kg,oral)-and carvacrol(25–100 mg/kg,oral)-treated groups.LPS was in-jected daily for 14 days.Treatment with ZME and carvacrol started 3 days before LPS administration and treatment continued during LPS administration.At the end of the study,the levels of malondialdehyde(MDA),NO,thiols,and antioxidant enzymes were evaluated.Results:Our findings showed a significant reduction in the levels of superoxide dis-mutase(SOD),catalase(CAT),and thiols in the LPS group,which were restored by ZME and carvacrol.Furthermore,ZME and carvacrol decreased MDA and NO in car-diac and aortic tissues of LPS-injected rats.Conclusions:The results suggest protective effects of ZME and carvacrol on LPS-induced cardiovascular injury via improved redox hemostasis and attenuated NO pro-duction.However,additional studies are needed to elucidate the effects of ZME and its constituents on inflammatory responses mediated by LPS.

Lycium barbarum polysaccharides protects retinal ganglion cells against oxidative stress injury

The accumulation of excessive reactive oxygen species can exacerbate any injury of retinal tissue because free radicals can trigger lipid peroxidation,protein damage and DNA fragmentation.Increased oxidative stress is associated with the common pathological process of many eye diseases,such as glaucoma,diabetic retinopathy and ischemic optic neuropathy.Many studies have demonstrated that Lycium barbarum polysaccharides(LBP)protects against oxidative injury in numerous cells and tissues.For the model of hypoxia we used cultured retinal ganglion cells and induced hypoxia by incubating with 200μM cobalt chloride(CoCl2)for 24 hours.To investigate the protective effect of LBP and its mechanism of action against oxidative stress injury,the retinal tissue was pretreated with 0.5 mg/mL LBP for 24 hours.The results of flow cytometric analysis showed LBP could effectively reduce the CoCl2-induced retinal ganglion cell apoptosis,inhibited the generation of reactive oxygen species and the reduction of mitochondrial membrane potential.These findings suggested that LBP could protect retinal ganglion cells from CoCl2-induced apoptosis by reducing mitochondrial membrane potential and reactive oxygen species.

Senna petersiana inhibits key digestive enzymes and modulates dysfunctional enzyme activities in oxidative pancreatic injury

Objective:To evaluate the effect of Senna petersiana leaf extracts on key digestive enzymes and FeSO_(4)-induced oxidative injury.Methods:Dried Senna petersiana leaf powder(60 g)was defatted in n-hexane and then extracted sequentially at room temperature with dichloromethane,methanol,and distilled water.The total phytochemical content of the extracts was estimated using established methods.The in vitro antioxidant,anti-lipase,and antidiabetic activities and the effect of the extracts on intestinal glucose absorption and FeSO_(4)-induced pancreatic oxidative injury were determined using different protocols.Moreover,GC-MS analysis was performed to identify the main compounds of the plant extract.Molecular docking analysis was also carried out to evaluate the binding energy of compounds with digestive enzymes.Results:Senna petersiana leaf extracts showed significant antioxidant activities in FRAP,DPPH,and hydroxyl radical scavenging assays.They also inhibited pancreatic lipase and lowered intestinal glucose absorption by suppressing activities ofα-amylase andα-glucosidase.Treatment with the extracts also lowered lipid peroxidation(malondialdehyde),nitric oxide level,acetylcholinesterase,and ATPase activities with simultaneous improvement of antioxidant(catalase,superoxide dismutase,glutathione)capacity in the type 2 diabetes model of oxidative pancreatic injury.GC-MS characterization of the extracts revealed the presence of stilbenoids,alkaloids,and other compounds.Molecular docking screening assay indicated the extract phytochemicals showed strong interaction with the active site amino acids of the targeted digestive enzymes.Among the Senna petersiana compounds,veratramine had the highest affinity forα-amylase and lipase,whereas dihydrostilbestrol was most attracted toα-glucosidase.Conclusions:Senna petersiana inhibits carbohydrate digestive enzymes,reduces intestinal glucose absorption,and exerts ameliorative effects on FeSO_(4)-induced oxidative pancreatic injury with significant antioxidant capabilities.Detailed in vivo studies are underway to understand the plant's therapeutic potential in diabetes management.

Yinhuang granule alleviates carbon tetrachloride-induced liver fibrosis in mice and its mechanism

BACKGROUND Liver fibrosis is a formidable global medical challenge,with no effective clinical treatment currently available.Yinhuang granule(YHG)is a proprietary Chinese medicine comprising Scutellariae Radix and Lonicerae Japonicae Flos.It is frequently used for upper respiratory tract infections,pharyngitis,as well as acute and chronic tonsillitis.AIM To investigate the potential of YHG in alleviating carbon tetrachloride(CCl4)-induced liver fibrosis in mice.METHODS To induce a hepatic fibrosis model in mice,this study involved intraperitoneal injections of 2 mL/kg of CCl4 twice a week for 4 wk.Meanwhile,liver fibrosis mice in the low dose of YHG(0.4 g/kg)and high dose of YHG(0.8 g/kg)groups were orally administered YHG once a day for 4 wk.Serum alanine/aspartate aminotransferase(ALT/AST)activity and liver hydroxyproline content were detected.Sirius red and Masson's trichrome staining assay were conducted.Realtime polymerase chain reaction,western-blot and enzyme-linked immunosorbent assay were conducted.Liver glutathione content,superoxide dismutase activity level,reactive oxygen species and protein carbonylation amount were detected.RESULTS The administration of YHG ameliorated hepatocellular injury in CCl4-treated mice,as reflected by decreased serum ALT/AST activity and improved liver histological evaluation.YHG also attenuated liver fibrosis,evident through reduced liver hydroxyproline content,improvements in Sirius red and Masson's trichrome staining,and lowered serum hyaluronic acid levels.Furthermore,YHG hindered the activation of hepatic stellate cells(HSCs)and ameliorated oxidative stress injury and inflammation in liver from CCl4-treated mice.YHG prompted the nuclear accumulation of nuclear factor erythroid 2-related factor 2(Nrf2)and upregulated the expression of Nrf2-dependent downstream antioxidant genes.In addition,YHG promoted mitochondrial biogenesis in liver from CCl4-treated mice,as demonstrated by increased liver adenosine triphosphate content,mitochondrial DNA levels,and the expression of peroxisome proliferator-activated receptor gamma coactivator 1 alpha and nuclear respiratory factor 1.CONCLUSION YHG effectively attenuates CCl4-induced liver fibrosis in mice by inhibiting the activation of HSCs,reducing inflammation,alleviating liver oxidative stress damage through Nrf2 activation,and promoting liver mitochondrial biogenesis.

Alcoholic liver injury:Influence of gender and hormones

This article discusses several subjects pertinent to a consideration of the role of gender and hormones in alcoholic liver injury (ALI). Beginning with an overview of factors involved in the pathogenesis of ALI, we review changes in sex hormone metabolism resulting from alcohol ingestion, summarize research that points to estrogen as a cofactor in ALI, consider evidence that gut injury is linked to liver injury in the setting of alcohol, and briefly review the limited evidence regarding sex hormones and gut barrier function. In both women and female animals, most studies reveal a propensity toward greater alcohol-induced liver injury due to female gender, although exact hormonal influences are not yet understood. Thus, women and their physicians should be alert to the dangers of excess alcohol consumption and the increased potential for liver injury in females.

Protective effect of extracorporeal membrane pulmonary oxygenation combined with cardiopulmonary resuscitation on post-resuscitation lung injury

BACKGROUND: Cardiac arrest(CA) is a critical condition that is a concern to healthcare workers. Comparative studies on extracorporeal cardiopulmonary resuscitation(ECPR) and conventional cardiopulmonary resuscitation(CCPR) technologies have shown that ECPR is superior to CCPR. However, there is a lack of studies that compare the protective effects of these two resuscitative methods on organs. Therefore, we aim to perform experiments in swine models of ventricular fibrillation-induced CA to study whether the early application of ECPR has advantages over CCPR in the lung injury and to explore the protective mechanism of ECPR on the post-resuscitation pulmonary injury.METHODS: Sixteen male swine were randomized to CCPR(CCPR;n=8;CCPR alone) and ECPR(ECPR;n=8;extracorporeal membrane oxygenation with CCPR) groups, with the restoration of spontaneous circulation at 6 hours as an endpoint. RESULTS: For the two groups, the survival rates between the two groups were not statistically significant(P>0.05), the blood and lung biomarkers were statistically significant(P<0.05), and the extravascular lung water and pulmonary vascular permeability index were statistically significant(P<0.01). Compared with the ECPR group, electron microscopy revealed mostly vacuolated intracellular alveolar type II lamellar bodies and a fuzzy lamellar structure with widening and blurring of the blood-gas barrier in the CCPR group.CONCLUSIONS: ECPR may have pulmonary protective effects, possibly related to the regulation of alveolar surface-active proteins and mitigated oxidative stress response postresuscitation.

Injury of cortical neurons is caused by the advanced glycation end products-mediated pathway

Advanced glycation end products lead to cell apoptosis, and cause cell death by increasing endoplasmic reticulum stress. Advanced glycation end products alone may also directly cause damage to tissues and cells, but the precise mechanism remains unknown. This study used primary cultures of rat cerebral cortex neurons, and treated cells with different concentrations of glycation end products （50, 100, 200, 400 mg/L）, and with an antibody for the receptor of advanced glycation end products before and after treatment with advanced glycation end products. The results showed that with increasing concentrations of glycation end products, free radical content increased in neurons, and the number of apoptotic cells increased in a dose-dependent manner. Before and after treatment of advanced glycation end products, the addition of the antibody against advanced glycation end-products markedly reduced hydroxyl free radicals, malondialdehyde levels, and inhibited cell apoptosis. This result indicated that the antibody for receptor of advanced glycation end-products in neurons from the rat cerebral cortex can reduce glycation end product-induced oxidative stress damage by suppressing glycation end product receptors. Overall, our study confirms that the advanced glycation end products-advanced glycation end products receptor pathway may be the main signaling pathway leading to neuronal damage.

Activation of the ERK 1/2 and STAT3 signaling pathways is required for 661W cell survival following oxidant injury

AIM: To evaluate the influence of hydrogen peroxide (H2O2) on mouse photoreceptor-derived 661W cell survival and to determine the effect of PD98059, an inhibitor for MEK1 (the direct upstream activator of ERK1/2), and S3I201, a STAT3-specific inhibitor on 661W cell survival after H2O2 exposure. METHODS: The mouse photoreceptor-derived 661W cells were cultured. 661W cells were treated for 12 hours with different concentrations (0, 0.25, 0.50, 0.75, 1mmol/L) of H2O2 and cell viability was determined by 3- (4, 5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide) (MTT) assay. 661W cells were treated with different concentrations H2O2 (0, 5, 10, 50, 500, 1000 mu mol/L) for 15 minutes or 1mmol/L H2O2 for different time points (0,5,10,15,30 minutes), and p-Tyr705-STAT3, STAT3, Phospho-p44/42 MAPK (Thr202/Tyr204), ERK1/2 were surveyed by immunoblot analysis. After treatment with 50 mu mol/L PD98059, or S3I201 for 1 hour, the inhibition efficiency of cell signal pathways was analyzed by immunoblot analysis and the effects of inhibitors on cell viability were determined by MTT. RESULTS: After treating with different concentrations of H2O2 for 12 hours, the cell viability of 661W cells decreased in concentration-dependent manner (P<0.05). Moreover, H2O2 induced phosphorylation of ERK1/2 and STAT3 in 661W cells (P <0.05). After pretreatment with 50 mu mol/L PD98059 or S3I201 for 1 hour, H2O2-induced phosphorylation of ERK1/2 or STAT3 was suppressed separately (P<0.05). Using PD98059 or S3I201 to inhibit ERK1/2 or STAT3 signal pathway, the cell viability of 661W cells decreased significantly (P<0.05). CONCLUSION: We demonstrated that the exposure of 661W cells to H2O2 increased the activation of ERK1/2 and STAT3 signal pathways. Activation of these pathways is required for 661W cell survival following oxidant injury.

Time representation of mitochondrial morphology and function after acute spinal cord injury

Changes in mitochondrial morphology and function play an important role in secondary damage after acute spinal cord injury. We recorded the time representation of mitochondrial morphology and function in rats with acute spinal cord injury. Results showed that mitochondria had an irregular shape, and increased in size. Mitochondrial cristae were disordered and mitochondrial membrane rupture was visible at 2–24 hours after injury. Fusion protein mitofusin 1 expression gradually increased, peaked at 8 hours after injury, and then decreased to its lowest level at 24 hours. Expression of dynamin-related protein 1, amitochondrial fission protein, showed the opposite kinetics. At 2–24 hours after acute spinal cord injury, malondialdehyde content, cytochrome c levels and caspase-3 expression were increased, but glutathione content, adenosine triphosphate content, Na＋-K＋-ATPase activity and mitochondrial membrane potential were gradually reduced. Furthermore, mitochondrial morphology altered during the acute stage of spinal cord injury. Fusion was important within the first 8 hours, but fission played a key role at 24 hours. Oxidative stress was inhibited, biological productivity was diminished, and mitochondrial membrane potential and permeability were reduced in the acute stage of injury. In summary, mitochondrial apoptosis is activated when the time of spinal cord injury is prolonged.

Expression of nitric oxide synthase in the spinal cord after selective brachial plexus injury

BACKGROUND: Some researches showed that motoneurons in spinal cord anterior horn wound die following brachial plexus injury, but the concrete mechanism of motoneurons death remains unclear. OBJECTIVE: To observe the expression of nitric oxide synthase (NOS) and survival of C7 motoneurons in spinal cord of rats after selective brachial plexus injury. DESIGN: A randomized controlled animal experiment. SETTING:Department of Anatomy, Sun Yet-sen Medical College, Sun Yet-sen University. MATERIALS: Totally 35 adult healthy male Sprague-Dawley rats with the body mass of 200-300 g were provided by Experimental Animal Center, Sun Yet-sen Medical College, Sun Yat-sen University. The rats were divided into control group (n =5) and experimental group(n =30) by random number table method, and the experimental group was divided into three injury subgroups: anterior root avulsion group, dorsal root transection group and spinal cord hemisection group, 10 rats in each group. There were horse anti-neuronal NOS (nNOS) polycolonal antibody (Sigma company) and nicotina mideadeninedinucleotide phosphate (NADPH-d) (Sigma Company). METHODS: The experiment was performed at Department of Anatomy, Sun Yet-sen Medical College, Sun Yet-sen University between September 2004 and April 2005. ①After anesthetizing the rats, the spinous process of second thoracic vertebra as a marker, the vertebra was exposed from C5 to T1 and the lamina of vertebra was unclenched, and spinal dura mater was carved to expose the spinal nerve dorsal roots of C5-T1. The right ventral root of C7 was avulsed, and the residual root was removed in anterior root avulsion group. The right ventral root of C7 was avulsed and the right dorsal roots of brachial plexus (C5-T1) were cut off in dorsal root transection group. In spinal cord hemisection group, the hemisection between the C5 and C6 spinal segment on right side and avulsion of right ventral root of C7 were made. In the control group, the vertebra from C5 to T1 was unclenched and the skin of wound was sutured. ②Three weeks after operation, behavior of rats was observed. The rats were killed after anesthesia. The C7 segment of spinal cord was removed and treated with NADPH-d staining, neutral red counterstaining and NOS immunohistochemistry staining to detect the expression of NOS. MAIN OUTCOME MEASURES: The expression of NOS and survival of C7 motoneurons in spinal cord of rats 3 weeks after operation. RESULTS: Among the 35 included rats, 3 rats died 2 weeks following operation, so totally 32 rats were involved in the result analysis. ①NADPH-d positive neurons of in anterior horn of C7 in the three groups: The NADPH-d positive neurons could be found in anterior horn of C7 in the three groups. The percentage of that in anterior root avulsion group to that of non-injury side of spinal cord was(20.98±2.65)%, (29.43±6.81)% in dorsal root transection group and (31.74±6.80)% in spinal cord hemisection group. There was significant difference among the three injury groups(F =5.135,P =0.016). There was significant difference in anterior root avulsion group with dorsal root transection group and spinal cord hemisection group (t =2.562,3.167,P < 0.05). There was no significant difference between the dorsal root transection group and spinal cord hemisection group (P =0.534). ②survival rate of motoneurons in anterior horn of C7: There were dead motoneurons in the three injury groups, the percentages of surviving motoneurons to that of non-injured side of spinal cord were (69.22±4.04)%,(62.01±3.82)% and (56.74±6.86)%, respectively. There were significant differences among the three groups (F =9.508,P =0.002). The anterior root avulsion group was significantly different from the other two groups(t =2.764,4.587,P < 0.05). There was no significant difference between the dorsal root transection group and spinal cord hemisection group(P =0.073). CONCLUSION: The selective brachial plexus injury can induce the up-regulation of NOS expression in motorneurons of spinal cord anterior horn and block descending pathway of cortex to cause the more significant up-regulation of NOS and low survival rate in motoneurons. It indicates that descending pathway of cortex can inhibit the NOS expression in motorneurons of spinal cord anterior horn, and the high NOS expression might induce the death of motorneurons in spinal cord anterior horn.

Rosmarinic acid elicits neuroprotection in ischemic stroke via Nrf2 and heme oxygenase 1 signaling

Rosmarinic acid（RA） can elicit a neuroprotective effect against ischemic stroke, but the precise molecular mechanism remains poorly understood. In this study, an experimental ischemic stroke model was established in CD-1 mice（Beijing Vital River Laboratory Animal Technology, Beijing, China） by occluding the right middle cerebral artery for 1 hour and allowing reperfusion for 24 hours. After intraperitoneally injecting model mice with 10, 20, or 40 mg/kg RA, functional neurological deficits were evaluated using modified Longa scores. Subsequently, cerebral infarct volume was measured using TTC staining and ischemic brain tissue was examined for cell apoptosis with TUNEL staining. Superoxide dismutase activity and malondialdehyde levels were measured by spectrophometry. Expression of heme oxygenase-1（HO-1）, nuclear factor erythroid 2-related factor 2（Nrf2）, Bcl-2, Bax, Akt, and phospho-Ser473 Akt proteins in ischemic brain tissue was detected by western blot, while mRNA levels of Nrf2, HO-1, Bcl-2, and Bax were analyzed using real time quantitative PCR. In addition, HO-1 enzyme activity was measured spectrophotometrically. RA（20 and 40 mg/kg） greatly improved neurological function, reduced infarct volume, decreased cell apoptosis, upregulated Bcl-2 protein and mRNA expression, downregulated Bax protein and mRNA expression, increased HO-1 and Nrf2 protein and mRNA expression, increased superoxide dismutase activity, and decreased malondialdehyde levels in ischemic brain tissue of model mice. However, intraperitoneal injection of a HO-1 inhibitor（10 mg/kg zinc protoporphyrin IX） reversed the neuroprotective effects of RA on HO-1 enzyme activity and Bcl-2 and Bax protein expression. The PI3 K/Akt signaling pathway inhibitor LY294002（10 mM） inhibited Akt phosphorylation, as well as Nrf2 and HO-1 expression. Our findings suggest that RA has anti-oxidative and anti-apoptotic properties that protect against ischemic stroke by a mechanism involving upregulation of Nrf2 and HO-1 expression via the PI3 K/Akt signaling pathway.

The neuroprotective effect of walnut-derived peptides against glutamate-induced damage in PC12 cells: mechanism and bioavailability

In our previous study, defatted walnut meal hydrolysate(DWMH) could attenuate D-galactose-induced acute memory deficits in vivo, and six potent active peptides including WSREEQ, WSREEQE, WSREEQEREE, ADIYTE, ADIYTEEAG and ADIYTEEAGR were identified. The aim of this study was to investigate the possible mechanism underlying their neuroprotective effects on glutamate-induced apoptosis in PC12 cells and their digestive stability. Results showed that all these peptides could attenuate the reduction of cell viability caused by glutamate in PC12 cells, especially WSREEQEREE and ADIYTEEAGR. The addition of Arg residue in WSREEQEREE and ADIYTEEAGR might be the potential reason for their stronger protective effects. Additionally, these two peptides possibly protected PC12 cells against glutamate-induced apoptosis via activating intracellular antioxidant defence(superoxide dismutase(SOD) and glutathione peroxidase(GSH-Px)) through Kelch-like ECH-associated protein 1(Keap1) inhibition, inhibiting ROS production, Ca;influx and mitochondrial membrane potential(MMP) collapse as well as regulating the expression of apoptosis-related proteins(Bax and Bcl-2). This might be due to the presence of Trp, Tyr and Arg in these two peptides. However, encapsulation of WSREEQEREE and ADIYTEEAGR should be considered based on their digestive sensibility during in vitro gastrointestinal digestion.

PROTECTIVE EFFECTS OF MELATONIN ON CULTURED RAT CARDIOMYOCYTES DAMAGED BY H_2O_2

Objective.To investigate the protective effects of melatonin(MT )on cardiomyocytes against the ox-idative injury induced by H 2 O 2 .Methods.Ventricular myocytes were isolated from neonatal rats and cultured for3～5days.Cells were divided into4groups:control group,H 2 O 2 (100μmol/L H 2 O 2 )group,MT group(100μmol/L MT )and MT preconditioning group(100μmol/L MT+100μmol/L H 2 O 2 ).The fluorescent probe,DCFH?DA,was used to detect intracellular levels of reactive oxygen species(ROS)and another fluorescent probe,Fluo-3?AM,was used to detect[Ca 2+ ] i by using a laser scanning confocal microscopy(LSCM).The malondi-aldehyde(MDA)content in cardiomyocytes was determined by measuring thiobarbituric acid?reactive sub-stances to monitor lipid peroxidation.The activity of cytoplasmic enzyme lactate dehydrogenase(LDH)that was released into the culture media was assayed to indicate alternation in the integrity of the cellular membrane.Trypan blue exclusion was used to detect the cell viability.Results.Compared with the control group,intracellular ROS,[Ca 2+ ] i ,MDA content ,LDH leakage and cell death were significantly elevated when cells were treated by100μmol/L H 2 O 2 for60minutes(P<0.01).However,those changes were significantly attenuated in MT preconditioning group.Conclusion.MT has very good antioxidant effect and can protect the cardiomyocytes against H 2 O 2 -in-duced injury.

Hyperbaric oxygen preconditioning improves postoperative cognitive dysfunction by reducing oxidant stress and inflammation

Postoperative cognitive dysfunction is a crucial public health issue that has been increasingly studied in efforts to reduce symptoms or prevent its occurrence. However, effective advances remain lacking. Hyperbaric oxygen preconditioning has proved to protect vital organs, such as the heart, liver, and brain. Recently, it has been introduced and widely studied in the prevention of postoperative cognitive dysfunction, with promising results. However, the neuroprotective mechanisms underlying this phenomenon remain controversial. This review summarizes and highlights the definition and application of hyperbaric oxygen preconditioning, the perniciousness and pathogenetic mechanism underlying postoperative cognitive dysfunction, and the effects that hyperbaric oxygen preconditioning has on postoperative cognitive dysfunction. Finally, we conclude that hyperbaric oxygen preconditioning is an effective and feasible method to prevent, alleviate, and improve postoperative cognitive dysfunction, and that its mechanism of action is very complex, involving the stimulation of endogenous antioxidant and anti-inflammation defense systems.