Atorvastatin Alleviates Myocardial Ischemia-Reperfusion Injury via miR-26a-5p/FOXO1

Purpose: Ischemia-reperfusion (I/R) injury exacerbates myocardial cell death (including apoptosis and necrosis), leading to complications such as arrhythmias, myocardial stenosis, microvascular obstruction and heart failure, and it is particularly important to seek new strategies to mitigate reperfusion injury. In this paper, we will investigate whether atorvastatin can alleviate myocardial ischemia-reperfusion injury and verify its molecular mechanism. Methods: We successfully constructed a hypoxia-reperfusion (H/R) H9c2 cell model and transfected miR-26a-5p mimic, miR-26a-5p inhibitor and its negative control NC-mimic or NC-inhibitor into H9c2 cells using a transfection kit. The expression of miR-26a-5p and FOXO1 were detected by RT-qPCR assay, the expression of related proteins by Western blot assay, the cell viability of H9c2 cells by CCK-8 assay, the apoptosis rate of H9c2 cells by flow cytometry, the CK and LDH activity in cells by CK and LDH assay kits. The targeting relationship between miR-26a-5p and FOXO1 was verified by dual luciferase reporter gene assay. Results: MiR-26a-5p expression was decreased in H/R-induced cells and FOXO1 expression was increased in H/R-induced cells. Atorvastatin alleviated H/R injury in cardiomyocytes and was most effective at a concentration of 1 μM. Atorvastatin alleviated H/R injury in cardiomyocytes by upregulating miR-26a-5p expression, miR-26a-5p and FOXO1 were negatively regulated by targeting. Conclusion: Atorvastatin can alleviate H/R injury in cardiomyocytes by regulating miR-26a-5p/FOXO1.

Protective Effects of Zingiberis and Acniti Praeparatae Decoction on Myocardial IschemiaReperfusion Injury in Rats

This study aimed to investigate the protective effects of zin-giberis and acniti praeparatae decoction on oxidative stress injury induced by my-ocardial ischemia reperfusion in rats. [Method] Myocardial ischemia-reperfusion was performed by ligation of the left anterior descending coronary artery for 30 min, fol-lowed by reperfusion for 60 min. The effects of zingiberis and acniti praeparatae decoction on ECG ST segment, myocardial infarction percentage, malondialdehyde （MDA） content in the serum, superoxide dismutase （SOD） activity and other indica-tors were observed. [Result] Zingiberis and acniti praeparatae decoction could effec-tively inhibit ECG ST segment elevation caused by myocardial ischemia-reperfusion injuries, reduce the percentage of myocardial infarction, decline the content of MDA in the serum, and increase the activity of SOD. [Conclusion] Zingiberis and acniti praeparatae decoction exhibits protective effects on oxidative injuries caused by my-ocardial ischemia-reperfusion injuries in rats, which may be involved in reducing the formation of myocardial free radicals and enhancing antioxidant capacity of my-ocardium.

Comparative analysis of different cyclosporine A doses on protection after myocardial ischemia/reperfusion injury in rat

Objective:To investigate the protective effect of different cyclosporin A(CsA)doses on myocardial ischemia/reperfusion injury in rat models.Methods:A rat model of myocardial ischemia/reperfusion injury was established in vivo and the rats were randomly divided into four groups:placebo(PBS;T1),low-dose(CsA dose:1.0 mg/kg:T2),medium-dose(CsA dose:2.5 mg/kg:T3),and high-dose(CsA dose:5.0 mg/kg;T4)groups.Heart function indexes were monitored at different time points,the extent of myocardial infarction was assessed by Evans Blue-TTC staining,and creatine kinase MB mass and cardiac troponin 1 values were measured by biochemical assays.Results:Compared with the T1 and T2 groups,both the creatine kinase MB mass and cardiac troponin 1 were significantly lower in the T3 and T4 groups(P<0.05).The mean arterial pressure(MAP)and left ventricular systolic pressure(LVSP)decreased sequentially in each group,with the extending reperfusion time.Significant decreases in LVSP and MAP were observed in the T3 and T4 groups as compared to the T1 and T2 group(P<0.05)and the T2 group showed a significantly lower LVSP and MAP decline than the T1 group(P<0.05).Compared with the Tl group,the rats from the T2.T3,and T4 groups suffered from a significantly lower extent of myocardial infarction(P<0.05).Also,the a animals in the T3 and T4 groups had a significantly smaller extent of myocardial infarction than those in the T2 group(P<0.05).Conclusions:Various CsA doses exert different degrees of protection against ischemia/reperfusion injury,and this protective effect peaks at approximately 2.5 mg/kg in rat models.

Flow cytometric analysis of circulating microvesicles derived from myocardial ischemic preconditioning and cardioprotection of ischemia/reperfusion injury in rats

Objective: To establish a flow cytometric method to detect the alteration of phenotypes and concentration of circulating microvesicles(MVs) from myocardial ischemic preconditioning(IPC) treated rats(IPC-MVs), and to investigate the effects of IPC-MVs on ischemia/reperfusion(I/R) injury in rats. Methods: Myocardial IPC was elicited by three cycles of 5-min ischemia and 5-min reperfusion of the left anterior descending(LAD) coronary artery. Platelet-free plasma(PFP) was isolated through two steps of centrifugation at room temperature from the peripheral blood, and IPC-MVs were isolated by ultracentrifugation from PFP. PFP was incubated with anti-CD61, anti-CD144, anti-CD45 and anti-Erythroid Cells, and added 1, 2 μm latex beads to calibrate and absolutely count by flow cytometry. For functional research, I/R injury was induced by 30-min ischemia and 120-min reperfusion of LAD. IPC-MVs 7 mg/kg were infused via the femoral vein in myocardial I/R injured rats. Mean arterial blood pressure(MAP), heart rate(HR) and ST-segment of electrocardiogram(ECG) were monitored throughout the experiment. Changes of myocardial morphology were observed after hematoxylin-eosin(HE) staining. The activity of plasma lactate dehydrogenase(LDH) was tested by Microplate Reader. Myocardial infarct size was measured by TTC staining. Results: Total IPC-MVs and different phenotypes, including platelet-derived MVs(PMVs), endothelial cell-derived MVs(EMVs), leucocyte-derived MVs(LMVs) and erythrocyte-derived MVs(RMVs) were all isolated which were identified membrane vesicles(<1 μm) with corresponding antibody positive. The numbers of PMVs, EMVs and RMVs were significantly increased in circulation of IPC treated rats(P<0.05, respectively). In addition, at the end of 120-min reperfusion in I/R injured rats, IPC-MVs markedly increased HR(P<0.01), decreased ST-segment and LDH activity(P<0.05, P<0.01). The damage of myocardium was obviously alleviated and myocardial infarct size was significantly lowered after IPC-MVs treatment(P<0.01). Conclusion: The method of flow cytometry was successfully established to detect the phenotypes and concentration alteration of IPC-MVs, including PMVs, EMVs, LMVs and RMVs. Furthermore, circulating IPC-MVs protected myocardium against I/R injury in rats.

Cardioprotective effects of Salvia miltiorrhiza Bunge and Lignum dalbergiae odoriferae on rat myocardial ischemia/reperfusion injury

Aim Salvia miltiorrhiza Bunge （SM） and lignum dalbergiae odoriferae （DO） are both traditional Chi- nese medicine that have cardioprotective effects. Here, we further examined the combined effects of SM and DO on rat myocardial ischemia/reperfusion injury. The possible mechanism of SM and DO also were elucidated. Methods DO was divided into aqueous extract of lignum dalbergiae odoriferae （DOW） and lignum dalbergiae odoriferae oil （DOO）. Sprague-Dawley rats were randomized to seven groups： sham group, model group, treatment groups inclu- ding SM （10 g · kg^-1）, DOW （5 g · kg^-1）, DOO （0.5 ml · kg^-1）, SM ＋ DOW （10 g · kg^-1 ＋ 5 g · kg^-1）, SM ＋ DOO （ 10 g · kg^-1 ＋ 0. 5 ml · kg^-1）. Rats were pretreated with homologous drug for 7 days and then subjec- ted to 30 rain of ischemia followed by 180 rain of reperfusion. Electrocardiogram （ECG） and heart rate were moni- tored and recorded continuously. At the end of reperfusion, blood samples were collected to determine the serum levels of creatine kinase-MB （CK-MB） and lactate dehydrogenase （LDH）. Hearts were harvested to assess heart- body rate, infarct size and histopathological changes as well. Maximum and minimum effective points were deter- mined by measuring indicators associate with myocardial injury at different time-points of reperfusion （Smin, 15min, 30min, 45rain, 60min, 120min, 180min）. The potential therapeutic mechanism of SM and SM ＋ DOO were carried out by detecting superoxide dismutase （SOD）, malondialdehyde （MDA）, tumor necrosis factor-alpha （TNF-alpha） and interleukin 6 （IL-6）. Results The results showed SM and DO can ameliorate cardiac function respectively, and this cardioprotective effect was further strengthened by their combinations. Among all the combi- nations, SM ＋ DOO showed predominant potential to improve ECG and heart rate, reduce heart-body rate （28.5% ＋ 1.4% , P 〈 0.01 vs model） and myocardial infarct size （ 20.96% ＋ 1.61% , P 〈 0.01 vs model, P 〈 0.05 vs SM） , attenuate histopathological damage, decrease the levels of CK-MB and LDH （P 〈 0.01 vs model, P 〈 0.05 vs SM）. The maximum effective points of SM and SM ＋ DOO were 15min and 30rain respectively, and the minimum effective points of them were 180rain. In reducing serum level of MDA, TNF-alpha, IL-6 and increasing SOD activ- ity, SM ＋ DOO was similar to SM. Conclusion The results of this study indicated that SM ＋ DOO have combined effects that are highly effective than single pretreatment against myocardial ischemie reperfusion injury in rats. The possible mechanism of SM and DO were likely through its anti-oxidant and anti-inflammatory properties, and thus may be an effective and promising medicine for both prophylaxis and treatment of ischemic heart disease.

Mechanism of hesperidin improving myocardial ischemia/reperfusion injury in type 2 diabetic rats through SIRT1/Nrf2/HO-1 signaling pathway

Objective:To observe the protective effect of hesperidin on myocardial ischemia/reperfusion injury in type 2 diabetes mellitus and its effect on SIRT1/Nrf2/HO-1 signaling pathway.Methods:50 Sprague-Dawley(SD)rats were randomly assigned to the normal control group(NC),model group,ischemia-reperfusion group(IR),hesperidin group,SIRT1 inhibitor group and hesperidin plus SIRT1 inhibitor group.In addition to NC,the rats in the remaining groups were replicated by intraperitoneal of high-fat diet combined with injection of streptozotocin for type 2 diabetic rats.After then,the myocardial ischemia/reperfusion injury(MIRI)rat model was established by LAd for 30 minutes with 2 hours reperfusion.He staining was used to observe the pathological changes of myocardial tissue,and the levels of serum LDH,CK-MB and SOD,GSH and MDA in myocardial tissue were detected by kit methods,and the expression abundance of related proteins in 4-HNE and SIRT1/Nrf2/HO-1 signal pathway were detected by immunohistochemistry and Western blot;Results:Hesperidin could significantly inhibit cardiomyocyte necrosis and inflammatory cell infiltration,reduce LDH activity,CK-MB and MDA level,and increase SOD activity,GSH and 4-HNE level,the differences were statistically significant when compared with IR group(P<0.01).In addition,compared with the ischemia-reperfusion group,the expressions of SIRT1,Nrf2 and HO-1 proteins in hesperidin group were significantly up-regulated,the differences were statistically significant(P<0.01);Conclusion:Hesperidin inhibits oxidative stress by activating SIRT1/Nrf2/HO-1 signaling pathway,and play a protective effect of myocardial ischemia reperfusion injury in diabetic rats.

Experimental study that trimetazidine inhibits Fas/FasL pathway to relieve the myocardial ischemia reperfusion injury in rats

Objective: To study the protective effect and molecular mechanism of trimetazidine on myocardial ischemia reperfusion injury in rats. Methods: Adult male SD rats were chosen as the experimental animals and randomly divided into control group, ischemia reperfusion group and trimetazidine group, and myocardial ischemia reperfusion models were established and then given intraperitoneal injection of trimetazidine hydrochloride for intervention. The expression levels of Fas/FasL pathway molecules as well as the contents of inflammatory and oxidative stress molecules in the myocardium, and the contents of myocardial enzymes in the blood circulation were measured 120 min after reperfusion. Results: Fas, FasL, Caspase-8 and Caspase-3 mRNA expression as well as NK-κB, TNF-α, ICAM-1, IL-17, IL-23, NOX2, NOX4, AOPP and MDA contents in myocardium, and LDH, CK and CK-MB contents in blood circulation of ischemia reperfusion group were significantly higher than those of control group, and Fas, FasL, Caspase-8 and Caspase-3 mRNA expression as well as NK-κB, TNF-α, ICAM-1, IL-17, IL-23, NOX2, NOX4, AOPP and MDA contents in myocardium, and LDH, CK and CK-MB contents in blood circulation of trimetazidine group were significantly lower than those of ischemia reperfusion group;LDH, CK and CK-MB contents in blood circulation as well as NK-κB, TNF-α, ICAM-1, IL-17, IL-23, NOX2, NOX4, AOPP and MDA contents in myocardium of trimetazidine group were positively correlated with Fas and FasL mRNA expression. Conclusion: Trimetazidine can inhibit Fas/FasL pathway to reduce the myocardial damage caused by inflammatory response and oxidative stress response during myocardial ischemia reperfusion in rats.

Calpain system and its involvement in myocardial ischemia and reperfusion injury

Calpains are ubiquitous non-lysosomal Ca2+-dependent cysteine proteases also present in myocardial cytosol and mitochondria.Numerous experimental studies reveal an essential role of the calpain system in myocardial injury during ischemia,reperfusion and postischemic structural remodelling.The increasing Ca2+-content and Ca2+-overload in myocardial cytosol and mitochondria during ischemia and reperfusion causes an activation of calpains.Upon activation they are able to injure the contractile apparatus and impair the energy production by cleaving structural and functional proteins of myocytes and mitochondria.Besides their causal involvement in acute myocardial dysfunction they are also involved in structural remodelling after myocardial infarction by the generation and release of proapoptotic factors from mitochondria.Calpain inhibition can prevent or attenuate myocardial injury during ischemia,reperfusion,and in later stages of myocardial infarction.

MicroRNA-15a/b are up-regulated in response to myocardial ischemia/reperfusion injury

Objective Several studies have indicated that miR-15a,miR-15b and miR-16 may be the important regulators of apoptosis.Since attenuate apoptosis could protect myocardium and reduce infarction size,the present study was aimed to find out whether these miRNAs participate in regulating myocardial ischemia reperfusion （I/R） injury.Methods Apoptosis in mice hearts subjected to I/R was detected by TUNEL assay in vivo,while flow cytometry analysis followed by Annexin V/PI double stain in vitro was used to detect apoptosis in cultured cardiomyocytes which were subjected to hypoxia/reoxygenation （H/R）.Taqman real-time quantitative PCR was used to confirm whether miR-15a/15b/16 were involved in the regulation of cardiac I/R and H/R.Results Compared to those of the controls,I/R or H/R induced apoptosis of cardiomyocytes was significantly iucreased both in vivo （24.4％ ± 9.4％ vs.2.2％ ± 1.9％,P ＜ 0.01,n =5） and in vitro （14.12％ ±0.92％ vs.2.22％ ± 0.08％）.The expression of miR-15a and miR-15b,but not miR-16,was increased in the mice I/R model,and the results were consistent in the H/R model.Conclusions Our data indicate miR-15 and miR-15b are up-regulated in response to cardiac I/R injury,therefore,down-regulation of miR- 15a/b may be a promising strategy to reduce myocardial apoptosis induced by cardiac I/R injury.

Effect of rosiglitazone on rabbit model of myocardial ischemia-reperfusion injury

To explore mechanism and protective effect of rosiglitazone on myocardial ischemia reperfusion(I/R) injury.Methods:A total of 48 male Japanese white big-ear rabbits were randomly divided into control group(A),I/R group(B),low dose of rosiglitazone group(C),high dose of rosiglitazone group(D).Plasma concentration of and also reduced the concentration of plasma serum creatine kinase(CK),CK-MB.high-sensitivity C-reactive protein(hsCRP).ultrasuperoxide dismutase(SOD),malondialdehyde(MD.A).lactic acid glutathione skin peroxidase (C-SH-PX).nitric oxide(NO)and endothelin(ET) were measured 1 h later after I/R.Twenty-four hours after I/R the hearts were harvested for pathological and ultrastructural analysis.Area of myocardial infarction were tested.Results:Plasma concentration of CK,Ck-MB.hsCRP,NO. MDA and ET were decreased in C,D group compared with group B.Plasma concentration of T-SOD and GSH-Px were increased significantly in C.D group compared with group B.Compared with group B.pathological and ullraslructural changes in C and D group were slightly.There was significant difference in myocardial infarction area between group C.D and group B(P【0.05). Myocardial infarction area and arrhythmia rate were lower in group C,D compare with group B. Rosiglitazone may protect myocardium from I/R injury by enhancing T-SOD and GSH-Px concentration,inhibit inflammatory reaction,and improve endothelial function.

Selective ischemic-hemisphere targeting Ginkgolide B liposomes with improved solubility and therapeutic efficacy for cerebral ischemia-reperfusion injury

Cerebral ischemia-reperfusion injury(CI/RI)remains the main cause of disability and death in stroke patients due to lack of effective therapeutic strategies.One of the main issues related to CI/RI treatment is the presence of the blood-brain barrier(BBB),which affects the intracerebral delivery of drugs.Ginkgolide B(GB),a major bioactive component in commercially available products of Ginkgo biloba,has been shown significance in CI/RI treatment by regulating inflammatory pathways,oxidative damage,and metabolic disturbance,and seems to be a candidate for stroke recovery.However,limited by its poor hydrophilicity and lipophilicity,the development of GB preparations with good solubility,stability,and the ability to cross the BBB remains a challenge.Herein,we propose a combinatorial strategy by conjugating GB with highly lipophilic docosahexaenoic acid(DHA)to obtain a covalent complex GB-DHA,which can not only enhance the pharmacological effect of GB,but can also be encapsulated in liposomes stably.The amount of finally constructed Lipo@GB-DHA targeting to ischemic hemisphere was validated 2.2 times that of free solution in middle cerebral artery occlusion(MCAO)rats.Compared to the marketed ginkgolide injection,Lipo@GB-DHA significantly reduced infarct volume with better neurobehavioral recovery in MCAO rats after being intravenously administered both at 2 h and 6 h post-reperfusion.Low levels of reactive oxygen species(ROS)and high neuron survival in vitro was maintained via Lipo@GB-DHA treatment,while microglia in the ischemic brain were polarized from the pro-inflammatory M1 phenotype to the tissue-repairing M2 phenotype,which modulate neuroinflammatory and angiogenesis.In addition,Lipo@GB-DHA inhibited neuronal apoptosis via regulating the apoptotic pathway and maintained homeostasis by activating the autophagy pathway.Thus,transforming GB into a lipophilic complex and loading it into liposomes provides a promising nanomedicine strategy with excellent CI/RI therapeutic efficacy and industrialization prospects.

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.

Effect and mechanism of salvianolic acid B on the myocardial ischemiareperfusion injury in rats

Objective:To investigate the effect of salvianolic acid B on rats with myocardial ischemiareperfusion injury.Methods:SD rats were randomly divided into five groups(n=10 in each group):A sham operation group,B ischemic reperfusion group model group,C low dose salvianolic acid B group,D median dose salvianolic acid B group,E high dose salvianolic acid B group.One hour after establishment of the myocardial ischemia-reperfusion model,the concentration and the apoptotic index of the plasma level of myocardial enzymes(CTnⅠ,CKMB),SOD,MDA,NO,ET were,measured.Heart tissues were obtained and micro-structural changes were observed.Results:Compared the model group,the plasma CTnⅠ,CK-MB,MDA and ET contents were significantly increased,NO,T-SOD contents were decreased in the treatment group(group C,D,and E)(P<0.05);compared with group E,the plasma CTnⅠ,CKMB,MDA and ET levels were increased,the NO,T-SOD levels were decreased in groups C and D(P<0.05).Infarct size was significantly reduced,and the myocardial ultrastructural changes were improved significantly in treatment group.Conclusions:Salvianolic acid B has a significant protective effect on myocardial ischemia-reperfusion injury.It can alleviate oxidative stress,reduce calcium overload,improve endothelial function and so on.

The role of glycogen synthase kinase 3 beta in brain injury induced by myocardial ischemia/reperfusion injury in a rat model of diabetes mellitus

Myocardial ischemia/reperfusion injury can lead to severe brain injury.Glycogen synthase kinase 3 beta is known to be involved in myocardial ischemia/reperfusion injury and diabetes mellitus.However,the precise role of glycogen synthase kinase 3 beta in myocardial ischemia/reperfusion injury-induced brain injury is unclear.In this study,we observed the effects of glycogen synthase kinase 3 beta on brain injury induced by myocardial ischemia/reperfusion injury in diabetic rats.Rat models of diabetes mellitus were generated via intraperitoneal injection of streptozotocin.Models of myocardial ischemia/reperfusion injury were generated by occluding the anterior descending branch of the left coronary artery.Post-conditioning comprised three cycles of ischemia/reperfusion.Immunohistochemical staining and western blot assays demonstrated that after 48 hours of reperfusion,the structure of the brain was seriously damaged in the experimental rats compared with normal controls.Expression of Bax,interleukin-6,interleukin-8,terminal deoxynucleotidyl transferase d UTP nick end labeling,and cleaved caspase-3 in the brain was significantly increased,while expression of Bcl-2,interleukin-10,and phospho-glycogen synthase kinase 3 beta was decreased.Diabetes mellitus can aggravate inflammatory reactions and apoptosis.Ischemic post-conditioning with glycogen synthase kinase 3 beta inhibitor lithium chloride can effectively reverse these changes.Our results showed that myocardial ischemic post-conditioning attenuated myocardial ischemia/reperfusion injury-induced brain injury by activating glycogen synthase kinase 3 beta.According to these results,glycogen synthase kinase 3 beta appears to be an important factor in brain injury induced by myocardial ischemia/reperfusion injury.

Myocardial ischemia-reperfusion injury:Possible role of melatonin

Our knowledge and understanding of the pathophysiology of coronary atherosclerosis has increased enormously over the last 20 years.Reperfusion through thrombolysis or percutaneous coronary angioplasty is the standard treatment for preventing acute myocardial infarction.Early reperfusion is an absolute prerequisite for survival of the ischemic myocardium,but reperfusion itself may lead to accelerated and additional myocardial injury beyond that generated by ischemia alone.These outcomes,in a range of reperfusion-associated pathologies,are collectively termed "reperfusion injuries".Reactive oxygen species are known to be produced in large quantities in the first few minutes of the post-ischemia reperfusion process.Similarly,scientific evidence from the last 15 years has suggested that melatonin has beneficial effects on the cardiovascular system.The presence of vascular melatoninergic receptor binding sites has been demonstrated;these receptors are functionally linked to vasoconstrictor or vasodilatory effects of melatonin.It has been shown that patients with coronary heart disease have a low melatonin production rate,especially those with higher risk of cardiac infarction and/or sudden death.Melatonin attenuates molecular and cellular damage resulting from cardiac ischemia-reperfusion in which destructive free radicals are involved.

Acupuncture preconditioning protects against myocardial ischemia/reperfusion injury mediated apoptosis through miR-214/NCX1 activation: a hypothesis

Early reperfusion of ischemic cardiac tissue is usually the best option to improve clinical outcome of angina pectoris, especially of acute myocardial infarction. However, myocardial reperfusion may cause an abnormal increase of intracellular Ca^2+-mediated cardiomyocyte death and consequent loss of cardiac function, which is referred to myocardial ischemia/reperfusion (I/R) injury. Recently, the microRNA-214 (miR-214)/Na^+/Ca^2+ exchanger (NCX) 1 co-expression is a key factor in cellular protection against myocardial apoptosis for myocardial I/R injury. Once activated, miR-214/NCX1 axis can inhibit several Ca^2+ downstream signaling effectors that mediate cell death simultaneously. Studies have shown that acupuncture preconditioning has a protective effect on myocardial I/R injury, but its mechanism deserves further research. It has been proved that acupuncture preconditioning for ischemic myocardium successfully inhibit multiple Ca2+ handling related microRNAs that mediate cell death pathways, and miR-214 is one of its targets. In terms of clinical practice, coronary heart disease (CHD) patients benefit a lot from this intervention. However, there is barely no study correlating acupuncture preconditioning to the miR-214/NCX1 co-expression in patients with CHD. This review aims to discuss whether there is some evidence to justify a recommendation of acupuncture preconditioning in CHD patients as a non-pharmacological therapeutic method to activate the miR-214/NCX1 co-expression network model.

Epac1/Rap1 signaling pathway is involved in the pathogenesis of myocardial ischemia/reperfusion injury in rats

OBJECTIVE In this study we explored the role of Epac1-Rap1 pathway in the acute myocardial ischemia/reperfusion injury(MIRI) in vitro and in vivo.METHODS An acute myocardial ischemia/reperfusion injury model was established by the ligation of left anterior descending coronary.Myocardial architecture,fibers and apoptosis was evaluated by the Masson trichrome staining,Sirius red staining and TUNEL assay.H9c2 cells were subjected to hypoxia for 5 h followed by 1-h reoxygen.ation in vitro.Cell viability was measured by MTT assay and cellular injury was evaluated by measuring the release of lactate dehydrogenase(LDH).Western blot,real-time PCR and immunofluorescence were used to detect the expressions of Epac1 and relative downstream molecules.RESULTS Myocardial IR-induced cardiac apoptosis and accumulation of Epac1 and Rap1 in rat IR injury model.Direct Epac activation by 8-CPT(8-(4-chlorophenylthio)-2′-O-methyl-cAMP) exacerbated cardiomyocyte death and dysfunction following hypoxia-reoxygenation(H/R),selective activation of Epac in response to H/R was evident which enriched for cytosolic/membrane proteins and mRNA.Harmacological inhibitor of Epac(ESI-09) significantly ameliorated myocardial injury with the decline of Epac expression.Epac inhibitor and agonist studies also implicated the effect of Rap1,which is downstream of Epac in this pathway.The expression of Rap1 elevated when activated by Epac agonist and was blocked by Epac inhibitor.The same result was true for myocyte CaMK-II and intracellular calcium ions activation.Moreover,ESI-09 also increased ERK1/2 phosphorylation.CONCLUSION Our study reveal that Epac1/Rap1 signaling pathway is involved in the pathogenesis of myocardial I/R injury in rats,which provides evidence on the development of therapeutic strategies target this pathway for myocardial I/R injury.

CHANGES IN NEUROPEPTIDES AFTER MUSIC EXPOSURE 429Cardioprotective effect of ivabradine via the AMPK/SIRT1/PGC-1αsignaling pathway in myocardial ischemia/reperfusion injuryinduced in H9c2 cell

Post-resuscitation myocardial dysfunction(PRMD)is the most severe myocardial ischemia-reperfusion injury(MIRI)and is characterized by difficult treatment and poor prognosis.Research has shown the protective effects of the rational use of ivabradine(IVA)against PRMD,however,the molecular mechanisms of IVA remain unknown.In this study,an ischemia-reperfusion injury(IRI)model was established using hypoxic chambers.The results demonstrated that pretreatment with IVA reduced IRI-induced cytotoxicity and apoptosis.IVA attenuated mitochondrial damage,eliminated excess reactive oxygen species(ROS),suppressed IRI-induced ATP and NAD+,and increased the AMP/ATP ratio.We further found that IVA increased the mRNA levels of sirtuin 1(SIRT1)and peroxisome proliferator-activated receptor-γcoactivator 1α(PGC-1α)and upregulated the expression levels of phosphorylated AMP-activated protein kinase(p-AMPK)/AMPK,SIRT1,and PGC-1αproteins.Interestingly,no change in AMPK mRNA levels was observed.Cardiomyocyte energy metabolism significantly changed after IRI.The aim of this study was to demonstrate the cardioprotective effect of Ivabradine via the AMPK/SIRT1/PGC-1αsignaling pathway in myocardial ischemia/reperfusion injury-induced in H9c2 cell.

Blocking the Aryl Hydrocarbon Receptor Alleviates Myocardial Ischemia/Reperfusion Injury in Rats

Objective Restoring the blood perfusion of ischemic heart tissues is the main treatment for myocardial ischemia.However,the accompanying myocardial ischemia reperfusion injury(IRI)would aggravate myocardial damage.Previous studies have confirmed that aryl hydrocarbon receptor(AhR)is closely correlated to kidney and intestinal IRI.The present study aimed to explore the relationship between AhR and myocardial IRI.Methods An oxygen glucose deprivation/reoxygenation(OGD/R)model of H9c2 cells and an ischemia/reperfusion(I/R)model of Sprague-Dawley rat myocardium were established.OGD/R cells and myocardial IRI rats were treated with different concentrations of the AhR antagonist CH-223191 or agonist 6-formylindolo[3,2-b]carbazole(FICZ).Under the conditions of normoxia and hypoxia/reoxygenation,the activity of cardiomyocytes,lactate dehydrogenase(LDH)and cell reactive oxygen species(ROS)were detected.In rats,myocardial pathological damage and markers of myocardial injury were detected.Results According to the results of the cell viability,LDH and ROS tests in vitro,both CH-223191 and FICZ showed no myocardial protection under OGD/R conditions.However,the histological staining and analysis of myocardial injury marker LDH in vitro revealed that CH-223191 could significantly reduce the myocardial IRI.Conclusion AhR exhibited a different effect on myocardial IRI in vitro and in vivo.In vivo,CH-223191 could significantly alleviate the myocardial IRI,suggesting that inhibition of AhR may play a role in myocardial protection,and AhR may serve as a potential treatment target for myocardial IRI.

Research progress of TRP channel's protective effect on myocardial ischemia-reperfusion injury

Transient receptor potential(TRP)channels are a type of cation channel located on the cell membrane.TRP channels are divided into 7 subfamilies(TRPC,TRPA,TRPM,TRPV,TRPN,TRPP and TRPML)and widely expressed in myocardial tissue.In recent years,with the application of gene knockout and transgenic model animals,it has been found that members of the TRP channel subfamilies TRPM,TRPC and TRPV are closely related to myocardial ischemia-reperfusion injury.The activation or inhibition of TRP channels participates in the regulation of myocardial ischemia-reperfusion injury,reduces the infarct area of the myocardium,and exerts a protective effect.Therefore,this paper first summarizes the structural characteristics of TRPM,TRPC,and TRPV and their distribution in the cardiovascular system,and then summarizes the mechanisms of TRPM,TRPC,and TRPV that regulate myocardial ischemia and reperfusion,which will provide a certain theoretical basis for treatment of myocardial ischemia-reperfusion injury.