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.

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.

Long-Term Prognosis of Different Reperfusion Strategies for ST-Segment Elevation Myocardial Infarction in Chinese County-Level Hospitals:Insight from China Acute Myocardial Infarction Registry

Objective To evaluate the long-term prognosis of patients with ST-segment elevation myocardial infarction(STEMI)treated with different reperfusion strategies in Chinese county-level hospitals Methods A total of 2,514 patients with STEMI from 32 hospitals participated in the China Acute Myocardial Infarction registry between January 2013 and September 2014.The success of fibrinolysis was assessed according to indirect measures of vascular recanalization.The primary outcome was 2-year mortality.Results Reperfusion therapy was used in 1,080 patients(42.9%):fibrinolysis(n=664,61.5%)and primary percutaneous coronary intervention(PCI)(n=416,38.5%).The most common reason for missing reperfusion therapy was a prehospital delay>12 h(43%).Fibrinolysis[14.5%,hazard ratio(HR):0.59,95%confidence interval(CI)0.44–0.80]and primary PCI(6.8%,HR=0.32,95%CI:0.22–0.48)were associated with lower 2-year mortality than those with no reperfusion(28.5%).Among fibrinolysistreated patients,510(76.8%)achieved successful clinical reperfusion;only 17.0%of those with failed fibrinolysis underwent rescue PCI.There was no difference in 2-year mortality between successful fibrinolysis and primary PCI(8.8%vs.6.8%,HR=1.53,95%CI:0.85–2.73).Failed fibrinolysis predicted a similar mortality(33.1%)to no reperfusion(33.1%vs.28.5%,HR=1.30,95%CI:0.93–1.81).Conclusion In Chinese county-level hospitals,only approximately 2/5 of patients with STEMI underwent reperfusion therapy,largely due to prehospital delay.Approximately 30%of patients with failed fibrinolysis and no reperfusion therapy did not survive at 2 years.Quality improvement initiatives are warranted,especially in public health education and fast referral for mechanical revascularization in cases of failed fibrinolysis.

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.

Network-pharmacology-based research on protective effects and underlying mechanism of Shuxin decoction against myocardial ischemia/reperfusion injury with diabetes

BACKGROUND Patients with diabetes mellitus are at higher risk of myocardial ischemia/reperfusion injury(MI/RI).Shuxin decoction(SXT)is a proven recipe modification from the classic herbal formula"Wu-tou-chi-shi-zhi-wan"according to the traditional Chinese medicine theory.It has been successfully used to alleviate secondary MI/RI in patients with diabetes mellitus in the clinical setting.However,the underlying mechanism is still unclear.AIM To further determine the mechanism of SXT in attenuating MI/RI associated with diabetes.METHODS This paper presents an ensemble model combining network pharmacology and biology.The Traditional Chinese Medicine System Pharmacology Database was accessed to select key components and potential targets of the SXT.In parallel,therapeutic targets associated with MI/RI in patients with diabetes were screened from various databases including Gene Expression Omnibus,DisGeNet,Genecards,Drugbank,OMIM,and PharmGKB.The potential targets of SXT and the therapeutic targets related to MI/RI in patients with diabetes were intersected and subjected to bioinformatics analysis using the Database for Annotation,Visualization and Integrated Discovery.The major results of bioinformatics analysis were subsequently validated by animal experiments.RESULTS According to the hypothesis derived from bioinformatics analysis,SXT could possibly ameliorate lipid metabolism disorders and exert anti-apoptotic effects in MI/RI associated with diabetes by reducing oxidized low density lipoprotein(LDL)and inhibiting the advanced glycation end products(AGE)-receptor for AGE(RAGE)signaling pathway.Subsequent animal experiments confirmed the hypothesis.The treatment with a dose of SXT(2.8 g/kg/d)resulted in a reduction in oxidized LDL,AGEs,and RAGE,and regulated the level of blood lipids.Besides,the expression of apoptosis-related proteins such as Bax and cleaved caspase 3 was down-regulated,whereas Bcl-2 expression was up-regulated.The findings indicated that SXT could inhibit myocardial apoptosis and improve cardiac function in MI/RI in diabetic rats.CONCLUSION This study indicated the active components and underlying molecular therapeutic mechanisms of SXT in MI/RI with diabetes.Moreover,animal experiments verified that SXT could regulate the level of blood lipids,alleviate cardiomyocyte apoptosis,and improve cardiac function through the AGE-RAGE signaling pathway.

Effect of reperfusion strategy on QT dispersion in patients with acute myocardial infarction:Impact on in-hospital arrhythmia

BACKGROUND Myocardial ischemia and ST-elevation myocardial infarction(STEMI)increase QT dispersion(QTD)and corrected QT dispersion(QTcD),and are also associated with ventricular arrhythmia.AIM To evaluate the effects of reperfusion strategy[primary percutaneous coronary intervention(PPCI)or fibrinolytic therapy]on QTD and QTcD in STEMI patients and assess the impact of the chosen strategy on the occurrence of in-hospital arrhythmia.METHODS This prospective,observational,multicenter study included 240 patients admitted with STEMI who were treated with either PPCI(group I)or fibrinolytic therapy(group II).QTD and QTcD were measured on admission and 24 hr after reperfusion,and patients were observed to detect in-hospital arrhythmia.RESULTS There were significant reductions in QTD and QTcD from admission to 24 hr in both group I and group II patients.QTD and QTcD were found to be shorter in group I patients at 24 hr than those in group II(53±19 msec vs 60±18 msec,P=0.005 and 60±21 msec vs 69+22 msec,P=0.003,respectively).The occurrence of in-hospital arrhythmia was significantly more frequent in group II than in group I(25 patients,20.8%vs 8 patients,6.7%,P=0.001).Furthermore,QTD and QTcD were higher in patients with in-hospital arrhythmia than those without(P=0.001 and P=0.02,respectively).CONCLUSION In STEMI patients,PPCI and fibrinolytic therapy effectively reduced QTD and QTcD,with a higher observed reduction using PPCI.PPCI was associated with a lower incidence of in-hospital arrhythmia than fibrinolytic therapy.In addition,QTD and QTcD were shorter in patients not experiencing in-hospital arrhythmia than those with arrhythmia.

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.

Delay Times and Clinical Outcomes in Acute Myocardial Infarction: Comparison of Periods before and during the COVID-19 Pandemic—Myocardial Infarction and the Pandemic

Introduction: At the beginning of the COVID-19 pandemic, a drop in the number of patients treated for cardiac emergencies raised concern about cardiovascular mortality in that period. An increase in care delay for patients with ST-segment elevation myocardial infarction (STEMI) may have affected clinical outcomes. Objectives: To analyze delay times and clinical outcomes of patients with STEMI undergoing primary percutaneous coronary intervention (PPCI), before and during the COVID-19 pandemic. Methods: Retrospective observational study that included patients with STEMI undergoing PPCI from December 2018 to July 2021. The COVID-19 pandemic cases were divided into two groups: pandemic I—from March to August 2020;and pandemic II—from September 2020 to July 2021. Patients were compared according to the period of hospitalization. Primary outcomes were delay times in assistance and clinical outcomes (acute kidney injury [AKI], post-procedural vascular complications and in-hospital mortality). Results: 108 patients were included, 39 (36.1%) in the pre-pandemic period, 13 (12.1%) in pandemic I and 56 (51.8%) in pandemic II. Time from onset of symptoms to arrival at the service and door-to-balloon time did not differ significantly among groups. Vascular complications were more frequent during the pandemic (I and II) than in the pre-pandemic period (2.5% pre-pandemic vs 15.4% pandemic vs 12.5% pandemic II;p = 0.03). AKI incidence was similar in all three periods. There was a non-significant increase in in-hospital mortality during the COVID-19 pandemic. Conclusion: In patients with STEMI, there was an increase in vascular complications and a trend toward increased mortality during the COVID-19 pandemic. Delay times to admission and reperfusion did not differ significantly between before and during the pandemic.

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.

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.

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.

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.

Effects of Ethyl Pyruvate on Myocardial Apoptosis and Expression of Bcl-2 and Bax Proteins after Ischemia-reperfusion in Rats

In order to study the effects of ethyl pyruvate on cardiomyocyte apoptosis following ischemia/reperfusion （I/R） in vitro and the expression of Bcl-2 and Bax proteins, isolated rat hearts were perfused in a Langendorff model. Twenty-four rats were randomly divided into 3 groups （n=8 in each group）： control group was perfused for 120 min. In the I/R group, after 30 min stabilization the injury was induced by 30 min global ischemia followed by 60 min reperfusion. Ethyl pyruvate （EP） group was set up with the same protocol as I/R group except that it was supplied with 2 mmol/L EP 15 rain before ischemia and throughout reperfusion. Myocardial malonaldehyde （MDA） content was measured. Myocardial apoptotic index （AI） was tested by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling （TUNEL） method. The expression of anti-apoptotic protein Bcl-2 and pro-apoptotic protein Bax in cardiac myocytes was detected by immunohistochemistry. As compared with control group, the content of MDA, myocardial AI and the expression of Bcl-2, Bax proteins were increased significantly in I/R group, but the content of MDA, myocardial AI and the expression of Bax protein were decreased obviously and the expression of Bcl-2 protein was up-regulated in EP group （P〈0.05）. These results demonstrate that EP could inhibit apoptosis of cardiac myocytes possibly via alleviating oxidative stress, up-regulating Bcl-2 and down-regulating Bax proteins.

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.

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.

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.

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.

Fructose 1,6-diphosphate alleviates myocardial ischemia reperfusion injury in rats through JAK2/STAT3 pathway

Objective: To study the effect of fructose 1,6-diphosphate(FDP) on myocardial ischemia reperfusion injury in rats and its molecular mechanism.Methods: Male SPF SD rats were selected as experimental animals and randomly divided into four groups.Sham group received sham operation, I/R group were made into myocardial ischemia reperfusion injury models, FDP group were made into myocardial ischemia reperfusion injury models and then were given FDP intervention, and FDP+AG490 group were made into myocardial ischemia reperfusion injury models and then were given FDP and JAK2 inhibitor AG490 intervention.Results: CK, CK-MB, c Tn I and LDH contents in serum as well as Bax and Caspase-3 protein expression in myocardial tissue of I/R group were significantly higher than those of Sham group whereas Bcl-2, p-JAK2 and p-STAT3 protein expression in myocardial tissues were significantly lower than those of Sham group; CK, CK-MB, c Tn I and LDH contents in serum as well as Bax and Caspase-3 protein expression in myocardial tissue of FDP group were significantly lower than those of I/R group whereas Bcl-2, p-JAK2 and p-STAT3 protein expression in myocardial tissue were significantly higher than those of I/R group; CK, CK-MB, c Tn I and LDH contents in serum as well as Bax and Caspase-3 protein expression in myocardial tissue of FDP+AG490 group were significantly higher than those of FDP group whereas Bcl-2 protein expression in myocardial tissue was significantly lower than that of FDP group.Conclusion: FDP could reduce the myocardial ischemia reperfusion injury in rats by activating the JAK2/STAT3 pathway.

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

ObjectiveSeveral 研究显示了 miR-15a， miR-15b 和 miR-16 可以是 apoptosis 的重要管理者。后来稀释 apoptosis 能保护心肌层和还原剂梗塞尺寸，现在的学习被瞄准发现是否这些 miRNAs 参予调整心肌的局部缺血灌注( I/R )在受到 I/R 的老鼠心的 injury.MethodsApoptosis 被 TUNEL 试金在 vivo 检测，当流动 cytometry 分析由 Annexin V/PI 列在后面时，在 vitro 的两倍污点被用来在受到 hypoxia/reoxygenation ( H/R )的有教养的 cardiomyocytes 检测 apoptosis 。Taqman 即时量的 PCR 被用来证实 miR-15a/15b/16 是否涉及心脏的 I/R 的规定，控制， I/R 或 H/R 的到那些的 H/R.ResultsCompared 导致了 cardiomyocytes 的 apoptosis 显著地在 vivo 两个都被增加(24.4%&#x000b1；9.4% 对 2.2%&#x000b1；1.9% ， P &#x0003c；0.01， n = 5 ) 并且在 vitro (14.12%&#x000b1；0.92% 对 2.22%&#x000b1；0.08%) 。 miR-15a 和 miR-15b 的表达式，然而并非 miR-16 ，在鼠标 I/R 模型，和结果被增加在 H/R model.ConclusionsOur 数据是一致的显示因此， miR-15 和 miR-15b 响应心脏的 I/R 损害是起来调整的 miR-15a/b 的下面规定可以是有希望的策略减少心脏的 I/R 损害导致的心肌的 apoptosis 。