Buxu Tongyu Granule Alleviates Myocardial Ischemia by Activating Vascular Smooth Muscle Cell Soluble Guanylate Cyclase to Inhibit Abnormal Vasomotion

Myocardial ischemia is a serious threat to human health,and vascular dysfunction is its main cause.Buxu Tongyu(BXTY)Granule is an effective traditional Chinese medicine(TCM)for treating myocardial ischemia.However,the underlying mechanism of BXTY is still unclear.In this study,we demonstrate that BXTY ameliorates myocardial ischemia by activating the soluble guanylate cyclase(sGC)-30,50-cyclic guanosine monophosphate(cGMP)-protein kinase G(PKG)signaling pathway in vascular smooth muscle cells(VSMCs)to dilate the arteries.BXTY was given by gavage for ten consecutive days before establishing an animal model of acute myocardial ischemia in mice via the intraperitoneal injection of pituitrin.The results showed that BXTY alleviated the symptoms of myocardial ischemia induced by pituitrin in mice,including electrocardiogram abnormalities and changes in plasma enzymes.In addition,BXTY dilated pre-constricted blood vessels and inhibited the vasoconstriction of the superior mesenteric artery in a dose-dependent but endothelial-independent manner.These effects were eliminated by preincubating vascular rings with the sGC inhibitors NS 2028 or ODQ,or with the PKG inhibitor KT 5823.Moreover,BXTY increased the protein expression of sGC-b1 and the intracellular second messenger cGMP level in mouse aortic vascular smooth muscle cells(MOVAs).NS 2028 or ODQ reversed these effects of BXTY.The expression level of the cGMP downstream effector protein PKG-1 increased after treating MOVAs with BXTY.NS 2028,ODQ,or KT 5823 also reversed this effect of BXTY.In conclusion,BXTY can improve the symptoms of acute myocardial ischemia in mice,and activating the sGC-cGMP-PKG pathway in VSMCs to induce vasodilation is its key pharmacodynamic mechanism.

Inhibition of SLC26A4 regulated by electroacupuncture suppresses the progression of myocardial ischemia-reperfusion injury

Introduction:Myocardial ischemia-reperfusion(IR)injury has received widespread attention due to its damaging effects.Electroacupuncture(EA)pretreatment has preventive effects on myocardial IR injury.SLC26A4 is a Na+independent anion reverse transporter and has not been reported in myocardial IR injury.Objectives:Tofind potential genes that may be regulated by EA and explore the role of this gene in myocardial IR injury.Methods:RNA sequencing and bioinformatics analysis were performed to obtain the differentially expressed genes in the myocardial tissue of IR rats with EA pretreatment.Myocardial infarction size was detected by TTC staining.Serum CK,creatinine kinase-myocardial band,Cardiac troponin I,and lactate dehydrogenase levels were determined by ELISA.The effect of SLC26A4 on cardiomyocyte apoptosis was explored by TUNEL staining and western blotting.The effects of SLC26A4 on inflammation were determined by HE staining,ELISA,and real-time PCR.The effect of SLC26A4 on the NF-κB pathway was determined by western blotting.Results:SLC26A4 was up-regulated in IR rats but downregulated in IR rats with EA pretreatment.Compared with IR rats,those with SLC26A4 knockdown exhibited improved cardiac function according to decreased myocardial infarction size,reduced serum LDH/CK/CK-MB/cTnI levels,and elevated left ventricular ejection fraction and fractional shortening.SLC26A4 silencing inhibited myocardial inflammation,cell apoptosis,phosphorylation,and nuclear translocation of NF-κB p65.Conclusion:SLC26A4 exhibited promoting effects on myocardial IR injury,while the SLC26A4 knockdown had an inhibitory effect on the NF-κB pathway.These results further unveil the role of SLC26A4 in IR injury.

Integrated network pharmacology and metabolomics to explore the mechanisms of Shenzao dripping pill against chronic myocardial ischemia

Background:Shenzao dripping pill(SZDP)is empirically prescribed for treating cardiac diseases.Nevertheless,there is a lack of comprehensive knowledge regarding the underlying mechanisms contributing to its therapeutic effects.The objective of this study is to investigate the underlying mechanism of SZDP against chronic myocardial ischemia(CMI)in a rat model.Methods:In this study,we utilized electrocardiographic and echocardiographic detection along with pathological tissue analysis to evaluate the efficacy of SZDP.The integration of network pharmacology and metabolomics was conducted to investigate the mechanisms.Molecular docking and molecular dynamics simulations were used to validate the binding energy between the compounds of SZDP and the associated targets.Results:The results showed that SZDP was able to improve T wave voltage,reverse CMI abnormalities in ejection fraction and fractional shortening,and restore histopathological heart damage.Metabolomics results indicated that disturbances of metabolic profile in CMI rats were partly corrected after SZDP administration,mainly affecting purine metabolism.13-Docosenamide may be the potential metabolic biomarker of the therapeutic application of SZDP for CMI.Integrating network pharmacology and metabolomics,thiopurine S-methyltransferase(TPMT),xanthine dehydrogenase/oxidase(XDH),bifunctional purine biosynthesis protein ATIC(ATIC),and cytochrome p4501A1(CYP1A1)were identified as possible targets of SZDP to exert therapeutic effects by enhancing the metabolic levels of L-Tryptophan,Deoxyribose 1-phosphate and Phosphoribosyl formamidocarboxamide.Conclusion:SZDP has a therapeutic effect on CMI by regulating metabolite levels,acting on the targets of TMPT,XDH,ATIC,and CYP1A1,and reducing cardiomyocyte injury and myocardial fibrosis.

Long non-coding RNA-AK138945 regulates myocardial ischemia-reperfusion injury via the miR-1-GRP94 signaling pathway

Objective:Myocardial ischemia-reperfusion injury(MIRI)is one of the leading causes of death from cardiovascular disease in humans,especially in individuals exposed to cold environments.Long non-coding RNAs(lncRNAs)regulate MIRI through multiple mechanisms.This study explored the regulatory effect of lncRNA-AK138945 on myocardial ischemia-reperfusion injury and its mechanism.Methods:In vivo,8-to 12-weeks-old C57BL/6 male mice underwent ligation of the left anterior descending coronary artery for 50 minutes followed by reperfusion for 48 hours.In vitro,the primary cultured neonatal mouse ventricular cardiomyocytes(NMVCs)were treated with 100μmol/L hydrogen peroxide(H_(2)O_(2)).The knockdown of lncRNA-AK138945 was evaluated to detect cardiomyocyte apoptosis,and a glucose-regulated,endoplasmic reticulum stress-related protein 94(GRP94)inhibitor was used to detect myocardial injury.Results:We found that the expression level of lncRNA-AK138945 was reduced in MIRI mouse heart tissue and H2O2-treated cardiomyocytes.Moreover,the proportion of apoptosis in cardiomyocytes increased after lncRNA-AK138945 was silenced.The expression level of Bcl2 protein was decreased,and the expression level of Bad,Caspase 9 and Caspase 3 protein was increased.Our further study found that miR-1a-3p is a direct target of lncRNA-AK138945,after lncRNA-AK138945 was silenced in cardiomyocytes,the expression level of miR-1a-3p was increased while the expression level of its downstream protein GRP94 was decreased.Interestingly,treatment with a GRP94 inhibitor(PU-WS13)intensified H2O2-induced cardiomyocyte apoptosis.After overexpression of FOXO3,the expression levels of lncRNA-AK138945 and GRP94 were increased,while the expression levels of miR-1a-3p were decreased.Conclusion:LncRNA-AK138945 inhibits GRP94 expression by regulating miR-1a-3p,leading to cardiomyocyte apoptosis.The transcription factor Forkhead Box Protein O3(FOXO3)participates in cardiomyocyte apoptosis induced by endoplasmic reticulum stress through up-regulation of lncRNA-AK138945.

Therapeutic Effects and Potential Mechanisms of Glyasperin A against Myocardial Ischemia Based on Network Pharmacology and Molecular Docking

[Objectives]To explore the therapeutic effects and potential mechanisms of Glyasperin A(GAA)on myocardial ischemia(MI)based on network pharmacology and molecular docking.[Methods]The molecular structure of GAA was downloaded from Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform(TCMSP),and all targets of GAA were predicted by converting 3D model molecules into SMILES online tool and Swiss target prediction.Genecards database and DisGeNET database were used to find the targets related to MI,and then Venny 2.1.0 was used to generate the corresponding Wayne diagram,and then Cytoscape 3.9.1 software was used to construct the protein-protein interaction(PPI)network.With the help of DAVID database and Microbiology,the selected core targets were enriched and analyzed by gene ontology(GO),biological process(BP),and Kyoto Encyclopedia of Genes and Genomes(KEGG),and then the molecular docking between GAA and core targets was verified by AutoDock and Pymol software.[Results]A total of 1883 MI targets were screened,and in the protein-protein interaction network,AKT1,PTGS2,PPARG,ESR1,GSK3B were the proteins with higher values.Gene ontology and KEEG enrichment analysis showed that the biological processes involved mainly included inflammatory response,negative regulation of gene expression,and response to exogenous stimuli.Signaling pathways mainly include IL-17 signaling pathway,HIF-1 signaling pathway,and so on.The results of molecular docking showed that the binding energy of GAA and core protein was less than-5 Kcal/mol in four groups.These indicated that GAA with good binding had a certain therapeutic effect on myocardial ischemia.[Conclusions]Based on the systematic network pharmacology method,this study predicts the basic pharmacological effects and potential mechanisms of GAA in the treatment of MI,and reveals that GAA may treat MI through multiple targets and signaling pathways.It is expected to provide a basis for further study of its pharmacological mechanisms.

Research Progress on Myocardial Protection Strategies

Myocaridial protection aims to salvage myocardium from ischemia and reperfusion injury and to reduce infarct size and its consequences.After more than 30 years of development,the concept of ischemic preconditioning has evolved into"ischemic conditioning",a term that encompasses a number of related endogenous cardioprotective strategies,which can be applied either directly to the heart(ischemic preconditioning or postconditioning)or from afar,for example to a limb(remote ischemic preconditioning,preconditioning,or postconditioning).A variety of cardioprotective therapies have shown promising results in reducing infarct size and improving clinical outcomes in patients with ischemic heart disease.

Canonical transient receptor potential channel 1 aggravates myocardial ischemia-and-reperfusion injury by upregulating reactive oxygen species

The canonical transient receptor potential channel(TRPC)proteins form Ca^(2+)-permeable cation channels that are involved in various heart diseases.However,the roles of specific TRPC proteins in myocardial ischemia/reperfusion(I/R)injury remain poorly understood.We observed that TRPC1 and TRPC6 were highly expressed in the area at risk(AAR)in a coronary artery ligation induced I/R model.Trpc1/mice exhibited improved cardiac function,lower serum Troponin T and serum creatine kinase level,smaller infarct volume,less fibrotic scars,and fewer apoptotic cells after myocardial-I/R than wild-type or Trpc6/mice.Cardiomyocyte-specific knockdown of Trpc1 using adeno-associated virus 9 mitigated myocardial I/R injury.Furthermore,Trpc1 deficiency protected adult mouse ventricular myocytes(AMVMs)and HL-1 cells from death during hypoxia/reoxygenation(H/R)injury.RNA-sequencing-based transcriptome analysis revealed differential expression of genes related to reactive oxygen species(ROS)generation in Trpc1/cardiomyocytes.Among these genes,oxoglutarate dehydrogenase-like(Ogdhl)was markedly downregulated.Moreover,Trpc1 deficiency impaired the calcineurin(CaN)/nuclear factorkappa B(NF-kB)signaling pathway in AMVMs.Suppression of this pathway inhibited Ogdhl upregulation and ROS generation in HL-1 cells under H/R conditions.Chromatin immunoprecipitation assays confirmed NF-kB binding to the Ogdhl promoter.The cardioprotective effect of Trpc1 deficiency was canceled out by overexpression of NF-kB and Ogdhl in cardiomyocytes.In conclusion,our findings reveal that TRPC1 is upregulated in the AAR following myocardial I/R,leading to increased Ca^(2+) influx into associated cardiomyocytes.Subsequently,this upregulates Ogdhl expression through the CaN/NF-kB signaling pathway,ultimately exacerbating ROS production and aggravating myocardial I/R injury.

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.

Mechanism of TLR-4/NF-κB pathway in myocardial ischemia reperfusion injury of mouse

Objective: To detect the expression of Toll-like receptor 4(TLR-4) and NF-κB and to discuss the mechanism of TLR-4/NF-κB pathway in the myocardial ischemia reperfusion injury of mouse. Methods: TLR-4 mutant mice and wild homozygous mice were divided into the model group and sham group. Mice in the model group were given the ligation of left anterior descending coronary artery for the modeling, while mice in the sham group were not given the ligation after threading. The cardiac muscle tissues were collected for the morphological observation. The immuno histochemistry was employed to detect the expression of NF-κB, Western blot was used to detect the expression of TLR-4 and ELISA to detect the expression of serum inflammatory factors. Results: The expression of NF-κB in TLR-4 null mice after the myocardial ischemia reperfusion was significantly lower than that in wild homozygous mice. For the model group and sham group, the expression of TLR-4 in wild homozygous mice was all significantly higher than that in TLR-4 null mice, while the expression of TLR-4 in TLR-4 null mice in the model group was significantly higher than that in sham group, with the statistical difference(P<0.05). The expression of inflammatory factors in TLR-4 null mice and wild homozygous mice in the model group was significantly higher than that in sham group. The expression of all factors in group A with TLR-4 null was significantly lower than that in group B with wild homozygous type, with the statistical difference(P<0.05). Conclusions: TLR-4/NF-κB pathway is closely related to the myocardial ischemia reperfusion injury, which plays its role through the release of inflammatory cytokines.

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.

GYY4137 protects against myocardial ischemia and reperfusion injury by attenuating oxidative stress and apoptosis in rats

Hydrogen sulfide （H2S） is a gasotransmitter that regulates cardiovascular functions. The present study aimed to determine the protective effect of slow-releasing H2S donor GYY4137 on myocardial ischemia and reperfusion （I/R） injury and to investigate the possible signaling mechanisms involved. Male Sprague-Dawley rats were treated with GYY4137 at 12.5 mg/（kg.day）, 25 mg/（kg.day） or 50 mg/（kg.day） intraperitoneally for 7 days. Then, rats were subjected to 30 minutes of left anterior descending coronary artery occlusion followed by reperfusion for 24 hours. We found that GYY4137 increased the cardiac ejection fraction and fractional shortening, reduced the ischemia area, alleviated histological injury and decreased plasma creatine kinase after myocardial I/R. Both H2S concentration in plasma and cystathionine-γ-lyase （CSE） activity in the myocardium were enhanced in the GYY4137 treated groups. GYY4137 also decreased malondialdehyde and myeloperoxidase levels in serum, attenuated superoxide anion level and suppressed phosphorylation of mitogen activated protein kinases in the myocardium after I/R. Meanwhile, GYY4137 increased the expression of Bcl-2 but decreased the expression of Bax, caspase-3 activity and apoptosis in the myocardium. The data suggest that GYY4137 protects against myocardial ischemia and reperfusion injury by attenuating oxidative stress and apoptosis.

Myocardial ischemia is a key factor in the management of stable coronary artery disease

Previous studies demonstrated that coronary revascularization,especially percutaneous coronary intervention(PCI),does not significantly decrease the incidence of cardiac death or myocardial infarction in patients with stable coronary artery disease.Many studies using myocardial perfusion imaging(MPI) showed that,for patients with moderate to severe ischemia,revascularization is the preferred therapy for survival benefit,whereas for patients with no to mild ischemia,medical therapy is the main choice,and revascularization is associated with increased mortality.There is some evidence that revascularization in patients with no or mild ischemia is likely to result in worsened ischemia,which is associated with increased mortality.Studies using fractional flow reserve(FFR) demonstrate that ischemia-guided PCI is superior to angiography-guided PCI,and the presence of ischemia is the key to decisionmaking for PCI.Complementary use of noninvasive MPI and invasive FFR would be important to compensate for each method's limitations.Recent studies of appropriateness criteria showed that,although PCI in the acute setting and coronary bypass surgery are properly performed in most patients,PCI in the non-acute set-ting is often inappropriate,and stress testing to identify myocardial ischemia is performed in less than half of patients.Also,some studies suggested that revascularization in an inappropriate setting is not associated with improved prognosis.Taken together,the presence and the extent of myocardial ischemia is a key factor in the management of patients with stable coronary artery disease,and coronary revascularization in the absence of myocardial ischemia is associated with worsened prognosis.

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.

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.

Protective Effects of Trimetazidine on Bone Marrow Mesenchymal Stem Cells Viability in an ex vivo Model of Hypoxia and in vivo Model of Locally Myocardial Ischemia

Bone marrow mesenchymal stem cells (MSCs) have shown potential for cardiac repair following myocardial injury,but this approach is limited by their poor viability after transplantation.The present study was to investigate whether trimetazidine (TMZ) could improve survival of MSCs in an ex vitro model of hypoxia,as well as survival,differentiation,and subsequent activities of transplanted MSCs in rat hearts with acute myocardial infarction (AMI).MSCs at passage 3 were examined for their viability and apoptosis under a transmission electron microscope,and by using flow cytometry following culture in serumfree medium and exposure to hypoxia (5% CO2,95% N2) for 12 h with or without TMZ.Thirty Wistar rats were divided into 3 groups (n=10 each group),including groupⅠ(AMI control),groupⅡ (MSCs transplantation alone),and group Ⅲ (TMZ+MSCs).Rat MSCs (4×107) were injected into peri-infarct myocardium (MSCs group and TMZ+MSCs group) 30 min after coronary artery ligation.The rats in TMZ+MSCs group were additionally fed on TMZ (2.08 mg?kg-1?day-1) from day 3 before AMI to day 28 after AMI.Cardiac structure and function were assessed by echocardiography at 28th day after transplantation.Blood samples were collected before the start of TMZ therapy (baseline),and 24 and 48 h after AMI,and inflammatory cytokines (CRP,TNF-α) were measured.Then the sur-vival and differentiation of transplanted cells in vivo were detected by immunofluorescent staining.The cellular apoptosis in the peri-infarct region was detected by using TUNEL assay.Furthermore,apoptosis-related proteins (Bcl-2,Bax) within the post-infarcted myocardium were detected by using Western blotting.In hypoxic culture,the TMZ-treated MSCs displayed a two-fold decrease in apoptosis under serumfree medium and hypoxia environment.In vivo,cardiac infarct size was significantly reduced,and cardiac function significantly improved in MSCs and TMZ+MSCs groups as compared with those in the AMI control group.Combined treatment of TMZ with MSCs implantation demonstrated further decreased MSCs apoptosis,further increased MSCs viability,further decreased infarct size,and further improved cardiac function as compared with MSCs alone.The baseline levels of inflammatory cyto-kines (CRP,TNF-α) had no significant difference among the groups.In contrast,all parameters at 24 h were lower in TMZ+MSCs group than those in MSCs group.Furthermore,Western blotting indicated that the expression of antiapoptotic protein Bcl-2 was upregulated,while the proapoptotic protein Bax was down-regulated in the TMZ+MSCs group,compared with that in the MSCs group.It is suggested that implantation of MSCs combined with TMZ treatment is superior to MSCs monotherapy for MSCs viability and cardiac function recovery.

Effects of Ang Ⅱ perfusion on transmural heterogeneous of Cx43 in acute myocardial ischemia reperfusion

Objective:To observe the effects of angiotensin Ⅱ(Ang Ⅱ) pefusion on transmural heterogeneity of Cx43 expression in the rabbit model with acute myocardial ischemia reperfusion(MIR),and investigate the role of rennin-angiotensin system in malignant ventricular arrhythmia induced by MIR.Methods:Twenty rabbits were randomly divided into MIR group(n=10) and Ang Ⅱ group(n=10).MIR model was produced with traditional ligation and opening of the anterior descending coronary artery in all animal.The hearts in vitro in the MIR group and the Ang Ⅱ group were perfused with simply improved Tyrode's solution and containing Ang Ⅱ Tyrode's solution respectively.90%monophasic action potential repolarization duration,transmural dispersion of repolarization.Cx43 protein(Cx43-pro) and mRNA(Cx43-Cq) expression in subepicardial,midmyocardial and subendocardial myocardium were measured in both groups.The greatest differences of Cx43-pro and Cx43-Cq among three myocardial layers were calculated and shown with △Cx43-pro and △Cx43-Cq respectively.Results:After Ang Ⅱ perfusion,90%monophasic action potential repolarization duration among three myocardial layer were significantly prolonged(P < 0.05 and P < 0.01),and transmural dispersion of repolarization also significantly increased compared with the MIR group(P < 0.05).Compare with the MIR group,three myocardial Cx43-pro and Cx43-Cq expression in the Ang Ⅱ group were significantly decreased(P < 0.05 and P < 0.01).but△Cx43-pro and △Cx43-Cq were significant increased.Conclusions:Renin-angiotensin system increases transmural heterogeneity of Cx43 expression in the rabbit model with MIR by Ang Ⅱ,and enlarge transmural dispersion of repolarization among three myocardial layers of left ventricular which induces malignant ventricular arrhythmia.

Effects of electroacupuncture on cardiac and gastric activities in acute myocardial ischemia rats

AIM： To observe the effect of electroacupuncture （EA） of ＂Neiguan＂ （PC6） and ＂Gongsun＂ （SP4） on pathological changes of the heart and stomach in rats with acute myocardial ischemia （AMI）, and to explore its underlying mechanism. METHODS： Fifty Wistar rats were randomized into control, model, PC6, SP4 and PC6 ＋ SP4 groups （n = 8 each group）. An AMI model was established by occlusion of the descending anterior branch （DAB） of the left coronary artery. ECG-ST of cervico-thoracic lead and electrogastrogram （EGG） were recorded. EA was applied to PC6, SP4 and PC6 ＋ SP4 groups, respectively. At the end of experiments, the rats were transcardicalty perfused with 4% paraformaldehyde, and the heart base myocardium, gastric antrum and duodenum tissues were sampled, sectioned and stained with a reduced form of nicotinamideadenine dinucleotide phosphate （NADPH）-diaphorase histochemical method for displaying nitric oxide synthase （NOS） activity. RESULTS： After AMI, ECG-ST values elevated. After EA, the elevated ECG-ST values at 20 min in PC6group, at 30 min in PC6 ＋ SP4 and SP4 groups had no significant differences in comparison with their respective basal values before AMI. Following AMI, the amplitude and frequency of slow waves of EGG decreased remarkably （P 〈 0.05）. At 30 min after EA, the mean amplitude and frequency of slow waves of EGG in the three EA groups had no marked differences compared with their individual basal levels and those in the control group. After AMI, the mean integral grey values of NOS-positive product in myocardium, gastric antrum and duodenum tissues in the model group increased remarkably in comparison with the control group, while those in three EA groups were lower than those in the model group. No significant differences were found in ECG-ST and EGG improvement among the three EA groups. However, EA of PC6 had a better effect on ECG-ST and EA of PC4 had a better effect on EGG, respectively. CONCLUSION： EA of PC6, SP4 and PC6 ＋ SP4 can significantly promote the recovery of cardiac and gastric electrical activities after AMI, and up-regulate NOS expression in myocardium, gastric antrum and duodenum tissues.

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.

Caffeoylquinic acid derivatives extract of Erigeron multiradiatus alleviated acute myocardial ischemia reperfusion injury in rats through inhibiting NF-kappaB and JNK activations

Erigeron multiradiatus(Lindl.)Benth.,has been used in Tibet folk medicine to treat various inflammatory diseases.The aim of this study was to investigate anti-myocardial ischemia and reperfusion(I/R)injury effect of caffeoylquinic acids derivatives of E.multiradiatus(AE)in vivo and to explain underling mechanism.AE was prepared using the whole plant of E.multiradiatus and contents of 6 caffeoylquinic acid determined through HPLC analysis.Myocardial I/R were induced by left anterior descending coronary artery occlusion for 30 min followed by 24 h of reperfusion in rats.AE administration(10,20 and 40 mg·kg-1)inhibited I/R-induced injury as indicated by decreasing myocardial infarct size,reducing of CK and LDH activities and preventing ST-segment depression in dose-dependent manner.AE decreased cardiac tissue levels of pro-inflammatory factors TNF-αand IL-6 and attenuated leukocytes infiltration.AE was further demonstrated to significantly inhibit I-κB degradation,nuclear translocation of p-65 and phosphorylation of JNK.Our results suggested that cardioprotective effect of AE could be due to suppressing myocardial inflammatory response and blocking NF-κB and JNK activation pathway.Thus,caffeoylquinic acids might be the active compounds in E.multiradiatus on myocardial ischemia and be a potential natural drug for treating myocardial I/R injury.