New progress in roles of nitric oxide during hepatic ischemia reperfusion injury

Hepatic ischemia reperfusion injury (HIRI) is a clinical condition which may lead to cellular injury and organ dysfunction. The role of nitric oxide (NO) in HIRI is complicated and inconclusive. NO produced by endothelial nitric oxide synthase (eNOS) activation plays a protective role during early HIRI. But eNOS overexpression and the resulting excessive NO bioavailability can aggravate liver injury. NO induced by inducible nitric oxide synthase (iNOS) may have either a protective or a deleterious effect during the early phase of HIRI, but it may protect the liver during late HIRI. Here, we reviewed the latest findings on the role of NO during HIRI: (1) NO exerts a protective effect against HIRI by increasing NO bioavailability, downregulating p53 gene expression, decreasing inflammatory chemokines, reducing ROS via inhibiting the mitochondrial respiratory chain, activating sGC-GTP-cGMP signal pathway to reduce liver cell apoptosis, and regulating hepatic immune functions; (2) eNOS protects against HIRI by increasing NO levels, several eNOS/NO signal pathways (such as Akt-eNOS/NO, AMPK-eNOS/NO and HIF-1 alpha-eNOS/NO) participating in the anti-HIRI process, and inhibiting over-expression of eNOS also protects against HIRI; and (3) the inhibition of iNOS prevents HIRI. Thus, the adverse effects of NO should be avoided, but its positive effect in the clinical treatment of diseases associated with HIRI should be recognized.

Nigella sativa relieves the deleterious effects of ischemia reperfusion injury on liver

AIM: To determine whether Nigella sativa prevents hepatic ischemia-reperfusion injury to the liver. METHODS: Thirty rats were divided into three groups as sham (Group 1), control (Group 2), and Nigella sati-va (NS) treatment group (Group 3). All rats underwent hepatic ischemia for 45 min followed by 60 min period of reperfusion. Rats were intraperitoneally infused with only 0.9% saline solution in group 2. Rats in group 3 received NS (0.2 mL/kg) intraperitoneally, before isch-emia and before reperfusion. Blood samples and liver tissues were harvested from the rats, and then the rats were sacrifi ced. Serum aspartate aminotransfera-se (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) levels were determined. Total antioxidant capacity (TAC), catalase (CAT), total oxida-tive status (TOS), oxidative stress index (OSI) and my-eloperoxidase (MPO) in hepatic tissue were measured. Also liver tissue histopathology was evaluated by light microscopy. RESULTS: The levels of liver enzymes in group 3 weresignifi cantly lower than those in the group 2. TAC in liver tissue was significantly higher in group 3 than in group 2. TOS, OSI and MPO in hepatic tissue were signifi cantly lower in group 3 than the group 2. Histo-logical tissue damage was milder in the NS treatment group than that in the control group. CONCLUSION: Our results suggest that Nigella sa-tiva treatment protects the rat liver against to hepatic ischemia-reperfusion injury.

Polyethylene glycols: An effective strategy for limiting liver ischemia reperfusion injury

Liver ischemia-reperfusion injury(IRI) is an inherent feature of liver surgery and liver transplantation in which damage to a hypoxic organ(ischemia) is exacerbated following the return of oxygen delivery(reperfusion). IRI is a major cause of primary nonfunction after transplantation and may lead to graft rejection, regardless of immunological considerations. The immediate response involves the disruption of cellular mitochondrial oxidative phosphorylation and the accumulation of metabolic intermediates during the ischemic period, and oxidative stress during blood flow restoration. Moreover, a complex cascade of inflammatory mediators is generated during reperfusion, contributing to the extension of the damage and finally to organ failure. A variety of pharmacological interventions(antioxidants, anticytokines, etc.) have been proposed to alleviate graft injury but their usefulness is limited by the local and specific action of the drugs and by their potential undesirable toxic effects. Polyethylene glycols(PEGs), which are non-toxic water-soluble compounds approved by the FDA, have been widely used as a vehicle or a base in food, cosmetics and pharmaceuticals, and also as adjuvants for ameliorating drug pharmacokinetics. Some PEGs are also currently used as additives in organ preservation solutions prior to transplantation in order to limit the damage associated with cold ischemia reperfusion. More recently, the administration of PEGs of different molecular weights by intravenous injection has emerged as a new therapeutic tool to protect liver grafts from IRI. In this review, we summarize the current knowledge concerning the use of PEGs as a useful target for limiting liver IRI.

Pentoxifylline enhances the protective effects of hypertonic saline solution on liver ischemia reperfusion injury through inhibition of oxidative stress

BACKGROUND：Liver ischemia reperfusion（IR）injury triggers a systemic inflammatory response and is the main cause of organ dysfunction and adverse postoperative outcomes after liver surgery.Pentoxifylline（PTX）and hypertonic saline solution（HTS）have been identified to have beneficial effects against IR injury.This study aimed to investigate if the addition of PTX to HTS is superior to HTS alone for the prevention of liver IR injury.METHODS： Male Wistar rats were allocated into three groups. Control rats underwent 60 minutes of partial liver ischemia, HTS rats were treated with 0.4 mL/kg of intravenous 7.5% NaCl 15 minutes before reperfusion, and HPTX group were treated with 7.5% NaC1 plus 25 mg/kg of PTX 15 minutes before reperfusion. Samples were collected after reperfusion for determination of ALT, AST, TNF-α, IL-6, IL-10, mitochondrial respiration, lipid peroxidation, pulmonary permeability and myeloperoxidase. RESULTS： HPTX significantly decreased TNF-α 30 minutes after reperfusion. HPTX and HTS significantly decreased ALT,AST, IL-6, mitochondrial dysfunction and pulmonary myelo- peroxidase 4 hours after reperfusion. Compared with HTS only, HPTX significantly decreased hepatic oxidative stress 4 hours after reperfusion and pulmonary permeability 4 and 12 hours after reperfusion. CONCLUSION： This study showed that PTX added the beneficial effects of HTS on liver IR injury through decreases of hepatic oxidative stress and pulmonary permeability.

Role of NF-kappaB in Liver Ischemia Reperfusion Injury of Rats

To determine the role of NF-kappaB in ischemia reperfusion (I/R) injury of the rat liver, rats underwent partial hepatic ischemia and reperfusion. The left and median lobes of the liver were subjected to ischemia for 90 min followed by reperfusion for defined times. NF-kappaB activity was analyzed by electrophoretic mobility shift assay (EMSA). Semiquantitative reverse-transcriptase polymerase chain reaction was used to analyze TNF-α and ICAM-1 mRNA levels. Results showed during liver I/R injury, NF-kappaB activation was induced in a time dependent manner. NF-kappaB was activated within 1h and 2h after the initiation of reperfusion and decreased after 4 h. Messenger RNA expression of TNF-α and ICAM-1 were increased after the reperfusion of 2 h. It was concluded that during hepatic I/R injury, NF-kappaB was activated and could bind to special sequence in the promoters of budget genes, which can up-regulate the expression of TNF-α and ICAM-1 mRNA to result in ischemia reperfusion injury of the rat liver.

Protective Effects of Epigallocatechin-3-gallate on Intestinal Ischemia Reperfusion Injury through Enhanced Activation of PI3K/Akt Pathway in Rats

Inflammation plays a critical role in intestinal ischemia reperfusion injury（IRI）. Epigallocatechin-3-gallate（EGCG） has been demonstrated to possess anti-inflammatory effect. This study examined the effect of EGCG on intestinal IRI and explored the possible mechanisms. Male Wistar rats were randomly divided into three groups： sham-operated group（Sham）, IRI control group（IRI） and IRI-EGCG group（EGCG）. Rats in IRI-EGCG group were administered dissolved EGCG in drinking water（0.4 mg/m L） for 14 days prior to IRI induction. A rat model of intestinal IRI was established by ligating the superior mesenteric artery（SMA） for 30 min, followed by reperfusion for 1 h. Intestinal histology, pro-inflammatory cytokines and mediators were examined and the effect of EGCG on PI3K/Akt signalling was assessed. EGCG significantly alleviated the pathological changes of the intestine and suppressed the IRI-induced up-regulation of TNF-α, IL-1 and IL-6 m RNA and protein expression in the serum and intestine. The mechanism might be that EGCG enhanced the activation of PI3K/Akt signalling pathway. In conclusion, the administration of EGCG can significantly mitigate the acute intestinal IRI in rats by enhancing the activation of PI3K/Akt signalling pathway to suppress inflammatory response and might be a promising alternative for the prevention or treatment of intestinal IRI in the clinical practice.

Effects of phycocyanin on apoptosis and expression of superoxide dismutase in cerebral ischemia reperfusion injury

BACKGROUND ： The application of exogenous antioxidant is always the focus in the prevention and treatment of cerebral ischemia. Phycocyanin has the effects against oxidation and inflammation, but its role in the pathophysiological process of cerebral ischemia reperfusion injury still needs further investigation. OBJECTIVE： To observe the effects of phycocyanin on the expression of superoxide dismutase （SOD） apoptosis and form of the nerve cells in rats after cerebral ischemia reperfusion injury. DESIGN： A randomized control animal experiment SETTING ： Institute of Cerebrovascular Disease, Medical School Hospital of Qingdao University MATERIALS： Fifty-two healthy adult male Wistar rats of clean degree, weighing 220-260 g, were used. Phycocyanin was provided by the Institute of Oceanology, Chinese Academy of Sciences. METHODS： The experiments were carried out in Shangdong Key Laboratory for Prevention and Treatment of Brain Diseases from May to December 2005. ① All the rats were divided into three groups according to the method of random number table： sham-operated group （n=4）, control group （n=24） and treatment group （n=24）. Models of middle cerebral artery occlusion/reperfusion （MCAO/R） were established by the introduction of thread through external and internal carotid arteries in the control group and treatment group. After 1-hour ischemia and 2-hour reperfusion, rats in the treatment group were administrated with gastric perfusion of phy- cocyanin suspension （0.1 mg/g）, and those in the control group were given saline of the same volume, and no treatment was given to the rats in the sham-operated group. ②The samples were removed and observed at ischemia for 1 hour and reperfusion for 6 and 12 hours and 1, 3, 7 and 14 days respectively in the control group and treatment group, 4 rats for each time point, and those were removed at 1 day postoperatively in the sham-operated group. Forms of the nerve cells were observed with toluidine blue staining. Apoptosis after cerebral ischemia reperfusion was detected with TUNEL technique. SOD expression was detected with immunohistochemical technique.③ The intergroup difference was compared with the ttest. MAIN OUTCOME MEASURES： The apoptosis of the nerve cells and SOD expression were mainly observed in each group. RESULTS： Finally, 52 rats were involved in the analysis of results. ① Number of apoptotic cells： In the sham-operated group, a few apoptotic cells could be observed in brain tissue. The apoptotic cells at each time point in the control group and treatment group were obviously more than those in the sham-operated group （P 〈 0.05）. In the treatment group, the numbers of apoptotic cells at 12 hours, 1 and 3 days after reperfusion were significantly fewer than those in the control group, and those at 6 hours, 7 and 14 days were similar to those in the control group. ② Number of SOD positive cells： In the sham-operated group, there was weak expression of SOD in brain tissue, and the positive cells were extremely few, the positive cells at each time point were significantly more in the control group and treatment group than in the sham-operated group （P 〈 0.05）. In the treatment group, the numbers of positive cells at 6 and 12 hours, 1 and 3 days after reperfusion were significantly fewer than those in the control group, and those at 7-14 days were similar to those in the control group. ③ Cellular forms： In the control group, the karyopyknosis occurred in the nerve cells, which were irregularly distributed, nucleolus disappeared, and some scattered cell fragments were observed. The forms of the nerve cells in the treatment group were generally normal. CONCLUSION ： Phycocyanin plays a neuroprotective role in cerebral ischemia reperfusion injury by activating the SOD expression and inhibiting apoptosis.

Effect and mechanism of adrenomedullin on apoptosis of renal tubular epithelial cell in rats induced by renal ischemia reperfusion injury

Objective To investigate the effect and mechanism of adrenomedullin ( AM ) on apoptosis of renal tubular epithelial cell in rats induced by renal ischemia reperfusion injury. Methods Thirty-two Wistar rats were randomly divided into 4 groups: control group,IRI group, empty plasmid group and AM group. One week after re-

The expression of oxidative stress genes related to myocardial ischemia reperfusion injury in patients with ST-elevation myocardial infarction

BACKGROUND:We aimed to investigate the gene expression of myocardial ischemia/reperfusion injury(MIRI)in patients with acute ST-elevation myocardial infarction(STEMI)using stress and toxicity pathway gene chip technology and try to determine the underlying mechanism.METHODS:The mononuclear cells were separated by ficoll centrifugation,and plasma total antioxidant capacity(T-AOC)was determined by the ferric reducing ability of plasma(FRAP)assay.The expression of toxic oxidative stress genes was determined and verified by oligo gene chip and quantitative real-time polymerase chain reaction(qRT-PCR).Additionally,gene ontology(GO)enrichment analysis was performed on DAVID website to analyze the potential mechanism further.RESULTS:The total numbers of white blood cells(WBC)and neutrophils(N)in the peripheral blood of STEMI patients(the AMI group)were significantly higher than those in the control group(WBC:11.67±4.85×10^(9)/L vs.6.41±0.72×10^(9)/L,P<0.05;N:9.27±4.75×10^(9)/L vs.3.89±0.81×10^(9)/L,P<0.05),and WBCs were significantly associated with creatine kinase-myocardial band(CK-MB)on the first day(Y=8.945+0.018X,P<0.05).In addition,the T-AOC was significantly lower in the AMI group comparing to the control group(12.80±1.79 U/mL vs.20.48±2.55 U/mL,P<0.05).According to the gene analysis,eight up-regulated differentially expressed genes(DEGs)included GADD45A,PRDX2,HSPD1,DNAJB1,DNAJB2,RAD50,TNFSF6,and TRADD.Four down-regulated DEGs contained CCNG1,CAT,CYP1A1,and ATM.TNFSF6 and CYP1A1 were detected by polymerase chain reaction(PCR)to verify the expression at different time points,and the results showed that TNFSF6 was up-regulated and CYP1A1 was down-regulated as the total expression.GO and kyoto encyclopedia of genes and genomes(KEGG)enrichment analysis suggested that the oxidative stress genes mediate MIRI via various ways such as unfolded protein response(UPR)and apoptosis.CONCLUSIONS:WBCs,especially neutrophils,were the critical cells that mediating reperfusion injury.MIRI was regulated by various genes,including oxidative metabolic stress,heat shock,DNA damage and repair,and apoptosis-related genes.The underlying pathway may be associated with UPR and apoptosis,which may be the novel therapeutic target.

A matrix metalloproteinase-responsive hydrogel system controls angiogenic peptide release for repair of cerebral ischemia/reperfusion injury

Vascular endothelial growth factor and its mimic peptide KLTWQELYQLKYKGI(QK)are widely used as the most potent angiogenic factors for the treatment of multiple ischemic diseases.However,conventional topical drug delivery often results in a burst release of the drug,leading to transient retention(inefficacy)and undesirable diffusion(toxicity)in vivo.Therefore,a drug delivery system that responds to changes in the microenvironment of tissue regeneration and controls vascular endothelial growth factor release is crucial to improve the treatment of ischemic stroke.Matrix metalloproteinase-2(MMP-2)is gradually upregulated after cerebral ischemia.Herein,vascular endothelial growth factor mimic peptide QK was self-assembled with MMP-2-cleaved peptide PLGLAG(TIMP)and customizable peptide amphiphilic(PA)molecules to construct nanofiber hydrogel PA-TIMP-QK.PA-TIMP-QK was found to control the delivery of QK by MMP-2 upregulation after cerebral ischemia/reperfusion and had a similar biological activity with vascular endothelial growth factor in vitro.The results indicated that PA-TIMP-QK promoted neuronal survival,restored local blood circulation,reduced blood-brain barrier permeability,and restored motor function.These findings suggest that the self-assembling nanofiber hydrogel PA-TIMP-QK may provide an intelligent drug delivery system that responds to the microenvironment and promotes regeneration and repair after cerebral ischemia/reperfusion injury.

Endoplasmic reticulum stress and autophagy in cerebral ischemia/reperfusion injury:PERK as a potential target for intervention

Several studies have shown that activation of unfolded protein response and endoplasmic reticulum(ER)stress plays a crucial role in severe cerebral ischemia/reperfusion injury.Autophagy occurs within hours after cerebral ischemia,but the relationship between ER stress and autophagy remains unclear.In this study,we established experimental models using oxygen-glucose deprivation/reoxygenation in PC12 cells and primary neurons to simulate cerebral ischemia/reperfusion injury.We found that prolongation of oxygen-glucose deprivation activated the ER stress pathway protein kinase-like endoplasmic reticulum kinase(PERK)/eukaryotic translation initiation factor 2 subunit alpha(e IF2α)-activating transcription factor 4(ATF4)-C/EBP homologous protein(CHOP),increased neuronal apoptosis,and induced autophagy.Furthermore,inhibition of ER stress using inhibitors or by si RNA knockdown of the PERK gene significantly attenuated excessive autophagy and neuronal apoptosis,indicating an interaction between autophagy and ER stress and suggesting PERK as an essential target for regulating autophagy.Blocking autophagy with chloroquine exacerbated ER stress-induced apoptosis,indicating that normal levels of autophagy play a protective role in neuronal injury following cerebral ischemia/reperfusion injury.Findings from this study indicate that cerebral ischemia/reperfusion injury can trigger neuronal ER stress and promote autophagy,and suggest that PERK is a possible target for inhibiting excessive autophagy in cerebral ischemia/reperfusion injury.

Treatment with β-sitosterol ameliorates the effects of cerebral ischemia/reperfusion injury by suppressing cholesterol overload, endoplasmic reticulum stress, and apoptosis

β-Sitosterol is a type of phytosterol that occurs naturally in plants.Previous studies have shown that it has anti-oxidant,anti-hyperlipidemic,anti-inflammatory,immunomodulatory,and anti-tumor effects,but it is unknown whetherβ-sitosterol treatment reduces the effects of ischemic stroke.Here we found that,in a mouse model of ischemic stroke induced by middle cerebral artery occlusion,β-sitosterol reduced the volume of cerebral infarction and brain edema,reduced neuronal apoptosis in brain tissue,and alleviated neurological dysfunction;moreover,β-sitosterol increased the activity of oxygen-and glucose-deprived cerebral cortex neurons and reduced apoptosis.Further investigation showed that the neuroprotective effects ofβ-sitosterol may be related to inhibition of endoplasmic reticulum stress caused by intracellular cholesterol accumulation after ischemic stroke.In addition,β-sitosterol showed high affinity for NPC1L1,a key transporter of cholesterol,and antagonized its activity.In conclusion,β-sitosterol may help treat ischemic stroke by inhibiting neuronal intracellular cholesterol overload/endoplasmic reticulum stress/apoptosis signaling pathways.

The action mechanism by which C1q/tumor necrosis factor-related protein-6 alleviates cerebral ischemia/reperfusion injury in diabetic mice

Studies have shown that C1q/tumor necrosis factor-related protein-6 (CTRP6) can alleviate renal ischemia/reperfusion injury in mice. However, its role in the brain remains poorly understood. To investigate the role of CTRP6 in cerebral ischemia/reperfusion injury associated with diabetes mellitus, a diabetes mellitus mouse model of cerebral ischemia/reperfusion injury was established by occlusion of the middle cerebral artery. To overexpress CTRP6 in the brain, an adeno-associated virus carrying CTRP6 was injected into the lateral ventricle. The result was that oxygen injury and inflammation in brain tissue were clearly attenuated, and the number of neurons was greatly reduced. In vitro experiments showed that CTRP6 knockout exacerbated oxidative damage, inflammatory reaction, and apoptosis in cerebral cortical neurons in high glucose hypoxia-simulated diabetic cerebral ischemia/reperfusion injury. CTRP6 overexpression enhanced the sirtuin-1 signaling pathway in diabetic brains after ischemia/reperfusion injury. To investigate the mechanism underlying these effects, we examined mice with depletion of brain tissue-specific sirtuin-1. CTRP6-like protection was achieved by activating the sirtuin-1 signaling pathway. Taken together, these results indicate that CTRP6 likely attenuates cerebral ischemia/reperfusion injury through activation of the sirtuin-1 signaling pathway.

Homer1a reduces inflammatory response after retinal ischemia/reperfusion injury

Elevated intraocular pressure(IOP)is one of the causes of retinal ischemia/reperfusion injury,which results in NRP3 inflammasome activation and leads to visual damage.Homerla is repo rted to play a protective role in neuroinflammation in the cerebrum.However,the effects of Homerla on NLRP3inflammasomes in retinal ischemia/reperfusion injury caused by elevated IOP remain unknown.In our study,animal models we re constructed using C57BL/6J and Homer1^(flox/-)/Homerla^(+/-)/Nestin-Cre^(+/-)mice with elevated IOP-induced retinal ischemia/repe rfusion injury.For in vitro expe riments,the oxygen-glucose deprivation/repe rfusion injury model was constructed with M uller cells.We found that Homerla ove rexpression amelio rated the decreases in retinal thickness and Muller cell viability after ischemia/reperfusion injury.Furthermore,Homerla knockdown promoted NF-κB P65^(Ser536)activation via caspase-8,NF-κB P65 nuclear translocation,NLRP3 inflammasome formation,and the production and processing of interleukin-1βand inte rleukin-18.The opposite results we re observed with Homerla ove rexpression.Finally,the combined administration of Homerla protein and JSH-23 significantly inhibited the reduction in retinal thickness in Homer1^(flox/-)Homer1a^(+/-)/Nestin-Cre^(+/-)mice and apoptosis in M uller cells after ischemia/reperfusion injury.Taken together,these studies demonstrate that Homer1a exerts protective effects on retinal tissue and M uller cells via the caspase-8/NF-KB P65/NLRP3 pathway after I/R injury.

N-acetylserotonin alleviates retinal ischemia-reperfusion injury via HMGB1/RAGE/NF-κB pathway in rats

AIM:To observe the effects of N-acetylserotonin(NAS)administration on retinal ischemia-reperfusion(RIR)injury in rats and explore the underlying mechanisms involving the high mobility group box 1(HMGB1)/receptor for advanced glycation end-products(RAGE)/nuclear factor-kappa B(NF-κB)signaling pathway.METHODS:A rat model of RIR was developed by increasing the pressure of the anterior chamber of the eye.Eighty male Sprague Dawley were randomly divided into five groups:sham group(n=8),RIR group(n=28),RIR+NAS group(n=28),RIR+FPS-ZM1 group(n=8)and RIR+NAS+FPS-ZM1 group(n=8).The therapeutic effects of NAS were examined by hematoxylin-eosin(H&E)staining,and retinal ganglion cells(RGCs)counting.The expression of interleukin 1 beta(IL-1β),HMGB1,RAGE,and nod-like receptor 3(NLRP3)proteins and the phosphorylation of nuclear factorkappa B(p-NF-κB)were analyzed by immunohistochemistry staining and Western blot analysis.The expression of HMGB1 protein was also detected by enzyme-linked immunosorbent assay(ELISA).RESULTS:H&E staining results showed that NAS significantly reduced retinal edema and increased the number of RGCs in RIR rats.With NAS therapy,the HMGB1 and RAGE expression decreased significantly,and the activation of the NF-κB/NLRP3 pathway was antagonized along with the inhibition of p-NF-κB and NLRP3 protein expression.Additionally,NAS exhibited an anti-inflammatory effect by reducing IL-1βexpression.The inhibitory of RAGE binding to HMGB1 by RAGE inhibitor FPS-ZM1 led to a significant decrease of p-NF-κB and NLRP3 expression,so as to the IL-1βexpression and retinal edema,accompanied by an increase of RGCs in RIR rats.CONCLUSION:NAS may exhibit a neuroprotective effect against RIR via the HMGB1/RAGE/NF-κB signaling pathway,which may be a useful therapeutic target for retinal disease.

Cholinergic anti-inflammatory pathway： a possible approach to protect against myocardial ischemia reperfusion injury

Objective A general review was made of studies involving： （1） the concept and mechanism of the cholinergic anti-inflammatory pathway （CAP）, （2） the important role of inflammatory response in myocardial ischemia reperfusion （I/R） injury and （3） the evidence and mechanisms by which CAP may provide protection against myocardial I/R injury. Data sources The data used in this review were mainly from manuscripts listed in PubMed that were published in English from 1987 to 2009. The search terms were ＂vagal nerve stimulation＂, ＂myocardial ischemia reperfusion injury＂, ＂nicotine acetylcholine receptor＂ and ＂inflammation＂. Study selection （1） Clinical and experimental evidence that the inflammatory response induced by reperfusion enhances myocardial I/R injury. （2） Clinical and laboratory evidence that the CAP inhibits the inflammation and provides protection against myocardial I/R injury. Results The myocardial I/R injury is really an inflammatory process characterized by recruitment of neutrophils into the ischemic myocardium and excessive production of pro-inflammatory cytokines. Because the CAP can modulate the inflammatory response by decreasing the production and release of pro-inflammatory cytokines, it can provide protection against myocardial I/R injury. Conclusions The CAP can inhibit the inflammatory response induced by reperfusion and protect against myocardial I/R injury. It represents an exciting opportunity to develop new and novel therapeutics to attenuate the myocardial I/R injury.

Effects of Acupuncture at Baihui(GV 20) and Zusanli(ST 36) on Peripheral Serum Expression of MicroRNA 124,Laminin and Integrin β1 in Rats with Cerebral Ischemia Reperfusion Injury

Objective： To explore the effects of acupuncture at Baihui （GV 20） and Zusanli （ST 36） on the peripheral serum expression of microRNA 124 （miRNA 124）, laminin and integrinβ 1 in rats with cerebral ischemia reperfusion injury （CIRI）. Methods： Seventy-two healthy male Sprague-Dawley rats were randomized into a model group, an acupuncture group, and a sham-operated group using a random digits table, with 24 rats per group. Each group was further randomly divided into 1-, 3-, 5-, and 7-day subgroups based on the reperfusion time according to a random digits table, with 6 rats in each subgroup. In the model and acupuncture groups, CIRI was induced using the thread occlusion method. Electroacupuncture stimulation was applied daily to GV 20 and left ST 36 for 20 min at the indicated time points after successful operations. Serum was sampled for detecting laminin and integrin β 1 protein via enzyme-linked immunosorbent assay, and serum miRNA 124 was examined using quantitative polymerase chain reaction. Results： The serum level of miRNA 124 in the cerebral ischemia rats increased significantly, and the peak expression of miRNA 124 in both the model and acupuncture groups occurred at 3 days. The expression of miRNA 124 in the acupuncture group was higher than in the model group at the same time point （5.96±0.01 vs. 3.11 ±0.04, P〈0.05）. Laminin expression in serum from the cerebral ischemia group was higher than that in the sham-operated group. Compared with the model group, the level of laminin in the serum of the acupuncture group was significantly lower at each time point, especially at the 3-day, and 7-day time points （589.12± 3.57 vs. 793.05± 5.28, and 600.53± 3.05 vs. 899.06± 5.74, P〈0.05）. The level of integrin 131 in the serum from the acupuncture group was lower than that in the model group particularly at the 3-day and Z-day time points （208.66± 0.95 vs. 280.83± 1.77, and 212.36±0.95 vs. 316.77±2.42, P〈0.05）. Additionally, the model group and the acupuncture group showed dual peaks of integrin β 1 and laminin expression at 3-day and 7-day. Conclusions： Acupuncture at GV 20 and ST 36 in rats alleviated CIRI and was associated with upregulated expression of miRNA 124 and with downregulated expression of integrin β 1 and laminin in peripheral serum. These changes may represent one of the mechanisms underlying acupuncture＇s attenuation of CIRI.

Combined postconditioning with ischemia and α7nAChR agonist produces an enhanced protection against rat myocardial ischemia reperfusion injury

Background Inflammation is one of important mechanisms for myocardial ischemia reperfusion injury （IRI）.Ischemia postconditioning （IPOC） can protect the heart against IRI by inhibiting inflammation,but its cardioprotection is weaker than that of ischemia preconditioning.Recently,the α7 subunit-containing nicotinic acetylcholine receptor （α7nAChR） agonist has shown anti-infiammatory effects in many diseases related to inflammation.This randomized controlled experiment was designed to evaluate whether combined postconditioning with IPOC and the α7nAChR agonist could produce an enhanced cardioprotection in a rat in vivo model of acute myocardial IRI.Methods Fifty Sprague-Dawley rats were randomly divided into five equal groups：sham group,control group,IPOC group,α7nAChR agonist postconditioning group （APOC group） and combined postconditioning with IPOC and α7nAChR agonist group （combined group）.Hemodynamic parameters were recorded during the periods of ischemia and reperfusion.Serum concentrations of troponin I （Tnl）,tumor necrosis factor α （TNF-α） and high-mobility group box 1 （HMGB-1） at 180 minutes after reperfusion were assayed in all groups.At the end of the experiment,the infarct size was assessed from excised hearts by Evans blue and triphenyl tetrazolium chloride staining.Results As compared to the sham group,the infarct size in the other four groups was significantly increased,serum levels of Tnl,TNF-α and HMGB1 in the control group and TNF-α,HMGB1 in the IPOC group were significantly increased.The infarct size and serum concentrations of TNF-α,HMGB1 and Tnl in the IPOC,APOC and combined groups were significantly lower than those in the control group.As compared to the IPOC group,the infarct size in the combined group was significantly decreased,serum concentrations of Tnl,TNF-α and HMGB1 in the APOC and combined groups were significantly reduced.Although the infarct size was significantly smaller in the combined group than in the APOC group,serum levels of TNF-α and HMGB1 were significantly higher in the combined group than in the APOC group.Conclusions In a rat in vivo model of acute myocardial IRI,combined postconditioning with IPOC and the α7nAChR agonist can produce enhanced protection against myocardial IRI by increasing the anti-inflammatory effect.

Propofol protects against blood-spinal cord barrier disruption induced by ischemia/reperfusion injury

Propofol has been shown to exert neuroprotective effects on the injured spinal cord.However,the effect of propofol on the blood-spinal cord barrier（BSCB） after ischemia/reperfusion injury（IRI） is poorly understood.Therefore,we investigated whether propofol could maintain the integrity of the BSCB.Spinal cord IRI（SCIRI） was induced in rabbits by infrarenal aortic occlusion for 30 minutes.Propofol,30 mg/kg,was intravenously infused 10 minutes before aortic clamping as well as at the onset of reperfusion.Then,48 hours later,we performed histological and m RNA/protein analyses of the spinal cord.Propofol decreased histological damage to the spinal cord,attenuated the reduction in BSCB permeability,downregulated the m RNA and protein expression levels of matrix metalloprotease-9（MMP-9） and nuclear factor-κB（NF-κB）,and upregulated the protein expression levels of occludin and claudin-5.Our findings suggest that propofol helps maintain BSCB integrity after SCIRI by reducing MMP-9 expression,by inhibiting the NF-κB signaling pathway,and by maintaining expression of tight junction proteins.

Morphological alterations and redox changes associated with hepatic warm ischemia-reperfusion injury

AIM To study the effects of warm ischemia-reperfusion(I/R) injury on hepatic morphology at the ultrastructural level and to analyze the expression of the thioredoxin(TRX)and glutaredoxin(GRX) systems.METHODS Eleven patients undergoing liver resection were subjected to portal triad clamping(PTC). Liver biopsies were collected at three time points; first prior to PTC(baseline), 20 min after PTC(post-ischemia) and 20 min after reperfusion(post-reperfusion). Electron microscopy and morphometry were used to study and quantify ultrastructural changes, respectively. Additionally, gene expression analysis of TRX and GRX isoforms was performed by quantitative PCR. For further validation of redox protein status, immunogold staining was performed for the isoforms GRX1 and TRX1.RESULTS Post-ischemia, a significant loss of the liver sinusoidal endothelial cell(LSEC) lining was observed(P = 0.0003) accompanied by a decrease of hepatocyte microvilli in the space of Disse. Hepatocellular morphology was well preserved apart from the appearance of crystalline mitochondrial inclusions in 7 out of 11 patients. Postreperfusion biopsies had similar features as post-ischemia with the exception of signs of a reactivation of the LSECs. No changes in the expression of redox-regulatory genes could be observed at mR NA level of the isoforms of the TRX family but immunoelectron microscopy indicated a redistribution of TRX1 within the cell.CONCLUSION At the ultrastructural level, the major impact of hepatic warm I/R injury after PTC was borne by the LSECs with detachment and reactivation at ischemia and reperfusion, respectively. Hepatocytes morphology were well preserved. Crystalline inclusions in mitochondria were observed in the hepatocyte after ischemia.