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.

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.

Studies on the Role of Sodium／Hydrogen Exchange System in Myocardial Ischemia－Reperfusion Injury

This study aimed at the exploration of the relationship between Na+-H+ exchange system and myocardial ischemia-reperfusion injury(MRI)in an attempt to provide a theoretic basis for the prevention and treatment of MRI.We used the isolated working guinea pig hearts as the experimental model to mimick cardiopulmonary bypass,which included 120 min hypothermic ischemic cardioplegic arrest followed by 60 min normothermic reperfusion.The hearts were divided into 2 groups:the control group receiving St.Thomas'Hospital Solution(STS)and the treated group receiving STS+ amiloride,a Na+-H+ exchangeblocker.The results showed that during reperfusion,[Na+]i and [Ca2+]i overloads,poor recovery of cardiac function,increases in CPK release and OFR generation,reduction of ATP content and serious damage of ultrastructure were seen in group 1;whereas there were no [Na+]i and [Ca2+]i overloads and better recovery of cardiac function accompanied by improved results of biochemical assay and less damage of ultrastructure was found in group 2.Our study indicates that amiloride can inhibit Na+-H+ exchange system in cardiac cells during early reperfusion period,which prevents [Na+]i overload produced by Na+-H+ exchange,and stops Na+-Ca2+ exchange activated by high level of [Na+]i,thus attenuating [Ca2+]ioverload caused by Na+-Ca2+ exchange and myocardial injury.Therefore,we conclude that Na+-H+ exchange blocker,amiloride,can exert significant protective effects on MRI and its use may prove to be a new clinical approach to prevention and cure of MRI.

Protective Effects of API_（0134） on Myocardial Ischemia and Reperfusion Injury

Previous studies have demonstrated that a crude extract from Chinese medicinal herb Andrographis Paniculata Nees (APN) could prevent myocardial ischemia and reperfusion injury. A refined extract API0134 was studied further. LAD was ligated for 90 min in 20 dogs and then reperfused for 120 min. The animals were randomly divided into 2 groups, API0134 treated group( n=10), 45 min after ischemia receiving a slow i. v. bolus of 1 mg/kg and then an infusion of 80 μg.kg-1/min for 60 min and control group (n=10) which was given only 5% glucose in saline. Result showed that the hemodynamics in API0134 treated group showed better effects of preventing the increase of the LVEDP and maintaining relatively normal CO as compared with control group. Ischemic ECGs were significantly milder. Malignant arrhythmia did not appear in API0134 treated group. After reperfusion, the infarct size was smaller ( 5. 06±2. 67 % vs 10. 45±3. 11 %, P < 0. 01 ), the damages found in myocardial ultrastructure were significantly milder. It is concluded that API0134 may protect the myocardium from ischemic reperfusion 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.

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.

Progress in protective effect and mechanism of 6-gingerol on myocardial ischemia/reperfusion injury

The morbidity and mortality of cardiovascular diseases are very high,which has attracted more and more attention all over the world.Common treatment methods for clinical treatment of acute myocardial infarction include direct percutaneous coronary intervention and coronary artery bypass grafting,which can quickly restore blocked coronary blood flow and reduce the infarct size.However,the inevitable ischemia/reperfusion injury will occur during the recovery of coronary blood flow,its pathological mechanism is complicated,and the Western medicine countermeasures are very limited.Among the current drugs for the treatment of cardiovascular diseases,traditional Chinese medicine has become a research hotspot due to its multiple targets,safety,and low side effects.Ginger is the fresh rhizome of Zingiber officinale Rosc.,a perennial herbaceous plant in the ginger family.It is a dual-purpose resource of medicine and food.Ginger has the functions of relieving the appearance and dispelling cold,warming up and relieving vomiting,resolving phlegm and relieving cough,and relieving fish and crab poison.The chemical components of ginger mainly include volatile oil,gingerol,diphenylheptane,etc..Among them,6-gingerol,as the main active component of gingerols,has obvious pharmacological effects in myocardial protection,anti-oxidation,anti-inflammatory,etc..Studies have shown that 6-gingerol protects myocardium mainly through anti-oxidative stress,anti-inflammatory,inhibiting cell apoptosis,and preventing calcium influx.①Anti-oxidative stress:oxidative stress is a state where oxidation and anti-oxidation in the body are out of balance,and it is also an important factor leading to myocardial damage.Many studies have confirmed that 6-gingerol has an antioxidant effect,and it is considered a natural antioxidant.6-gingerol can significantly reduce the degree of oxidative stress and the level of reactive oxygen species caused by cardiomyocyte damage,and has a significant cardioprotective effect.②Anti-inflammatory:inflammation can cause substantial cell damage and organ dysfunction,which is another important cause of myocardial damage.6-gingerol can reduce the levels of inflammatory factors such as interleukin-6,interleukin-1β,and tumor necrosis factor-αin cardiomyocytes,and at the same time inhibit the TLR4/NF-κB signaling pathway,an important regulatory pathway of inflammation,showing that it may improve myocardial damage through anti-inflammatory effects.③Inhibition of apoptosis:apoptosis is a complex and orderly process in the autonomous biochemical process of cells,and one of the main mechanisms of myocardial injury.This process can be roughly divided into three pathways:mitochondria,endoplasmic reticulum,and death receptors.Among them,the mitochondrial pathway plays an important role,and Bcl-2 and Bax located upstream of this pathway can regulate the entire process of cell apoptosis by regulating the permeability of the mitochondrial membrane.Studies have found that the preventive application of 6-gingerol can reduce cell damage,reduce the number of apoptotic cells,reduce the activity of Bax and caspase-3,and increase the expression of Bcl-2.Therefore,6-gingerol pretreatment can reduce the damage of cardiomyocytes,and its mechanism may be related to the inhibition of apoptosis.④Prevent calcium influx:calcium overload is involved in the pathogenesis of myocardial ischemic injury,which may be related to excessive contracture,arrhythmia,and mitochondrial Ca2+accumulation that impairs myocardial function.6-gingerol inhibits the increase of intracellular Ca2+concentration by inhibiting L-type calcium current,thereby reducing extracellular Ca2+influx,thereby avoiding calcium overload and playing a cardioprotective effect.In summary,6-gingerol can effectively treat and improve myocardial ischemia/reperfusion injury,and it has great development potential in the fields of medicine and health products.

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.

Changes of cTnI in myocardial ischemic and reperfusion injury during correction of cardiac defects in children

Objective The purpose of this study is to investgate changes of cTnI in myocardial ischemic and reperfusion injury during correction of cardiac defects in children. Methods From June, 1999 to May,2000,45 children (30 male, 15 female) undergoing correction of cardiac defects were divided into three groups randomly: group Ⅰ no myocardial ischemia,group Ⅱ myocardial ischemia less than 60 minutes, group Ⅲmyocardial ischemia 】 60 minutes. There were no significant differences in the three groups in age, sex ratio, C/T ratio, or left ventricular function. Blood samples for analysis were collected before skin incision and at time intervals up to 6 days postoperatively. Analysis of creatine kinase MB.LDH and cardiac-specific troponin I was used for the detection of myocardial damage. Meantime, the ECG was checked for myocardial infarction. After the reperfusion, myocardial tissue was obtained from the free wall of right ventricle myocardial structure studies. Results The level of cTnI was increased

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.

Effects of Lipoteichoic Acid induced Delayed Preconditioning on Ischemia-reperfusion Injury in Isolated Rat Hearts

To explore the potential of lipoteichoic acid (LTA) induced cardioprotection against ischemia-reperfusion (I/R) injury in isolated rat hearts and whether endogenous nitric oxide (NO) participates in the protection, the rats were pretreated with LTA (1 mg/kg, i p ) 24 h before the experiment, and the isolated hearts were subjected to 30 min no-flow normothermic global ischemia and 60 min reperfusion after a 20-min stabilization period by the langendorff method Cardiac functions were evaluated at the end of stabilization, and at 30 min, 60 min of reperfusion The amounts of MB isoenzyme of creatine kinase (CK-MB), lactate dehydrogenase(LDH) and total NO oxidation products in the coronary effluent were measured spectrophotometrically at the end of reperfusion It was revealed that pretreatment with LTA could significantly improve the recovery of cardiac function, reduce the release of CK-MB and LDH, and increase the concentrations of NO in coronary effluent The protective effects were abrogated by pretreatment of the rats with L-NAME It was concluded that LTA could induce the delayed cardioprotection against I/R injury, and endogenous NO may be involved in the mechanisms

Shuxuening Injection Inhibits Apoptosis and Reduces Myocardial Ischemia-Reperfusion Injury in Rats through PI3K/AKT Pathway

Objective: To investigate the main components and potential mechanism of Shuxuening Injection(SXNI) in the treatment of myocardial ischemia-reperfusion injury(MIRI) through network pharmacology and in vivo research. Methods: The Traditional Chinese Medicine Systems Pharmacology(TCMSP) and Pharm Mapper databases were used to extract and evaluate the effective components of Ginkgo biloba leaves, the main component of SXNI. The Online Mendelian Inheritance in Man(OMIM) and Gene Cards databases were searched for disease targets and obtain the drug target and disease target intersections. The active ingredient-target network was built using Cytoscape 3.9.1 software. The STRING database, Metascape online platform, and R language were used to obtain the key targets and signaling pathways of the anti-MIRI effects of SXNI. In order to verify the therapeutic effect of different concentrations of SXNI on MIRI in rats, 60 rats were first divided into 5 groups according to random number table method: the sham operation group, the model group, SXNI low-dose(3.68 mg/kg), medium-dose(7.35 mg/kg), and high-dose(14.7 mg/kg) groups, with 12 rats in each group. Then, another 60 rats were randomly divided into 5 groups: the sham operation group, the model group, SXNI group(14.7 mg/kg), SXNI+LY294002 group,and LY294002 group, with 12 rats in each group. The drug was then administered intraperitoneally at body weight for 14 days. The main biological processes were validated using in vivo testing. Evans blue/triphenyltetrazolium chloride(TTC) double staining, hematoxylin-eosin(HE) staining, terminal deoxynucleotidyl transferase d UTP nick end labeling(TUNEL) assay, enzyme-linked immunosorbent assay(ELISA), and Western blot analysis were used to investigate the efficacy and mechanism of SXNI in MIRI rats. Results: Eleven core targets and 30 Kyoto Encyclopedia of Genes and Genomes(KEGG) pathways were selected. Among these, the phosphoinositide 3-kinase(PI3K)/protein kinase B(AKT) pathway was closely related to SXNI treatment of MIRI. In vivo experiments showed that SXNI reduced the myocardial infarction area in the model group, improved rat heart pathological damage, and reduced the cardiomyocyte apoptosis rate(all P<0.01). After SXNI treatment, the p-PI3K/PI3K and p-AKT/AKT ratios as well as B-cell lymphoma-2(Bcl-2) protein expression in cardiomyocytes were increased, while the Bax and cleaved caspase 3 protein expression levels were decreased(all P<0.05). LY294002 partially reversed the protective effect of SXNI on MIRI. Conclusion: SXNI protects against MIRI by activating the PI3K/AKT signaling pathway.

Therapeutic Role of Chinese Medicine Targeting Nrf2/HO-1 Signaling Pathway in Myocardial Ischemia/Reperfusion Injury

Acute myocardial infarction(AMI),characterized by high incidence and mortality rates,poses a significant public health threat.Reperfusion therapy,though the preferred treatment for AMI,often exacerbates cardiac damage,leading to myocardial ischemia/reperfusion injury(MI/RI).Consequently,the development of strategies to reduce MI/RI is an urgent priority in cardiovascular therapy.Chinese medicine,recognized for its multi-component,multi-pathway,and multi-target capabilities,provides a novel approach for alleviating MI/RI.A key area of interest is the nuclear factor E2-related factor 2(Nrf2)/heme oxygenase-1(HO-1)pathway.This pathway is instrumental in regulating inflammatory responses,oxidative stress,apoptosis,endoplasmic reticulum stress,and ferroptosis in MI/RI.This paper presents a comprehensive overview of the Nrf2/HO-1 signaling pathway's structure and its influence on MI/RI.Additionally,it reviews the latest research on leveraging Chinese medicine to modulate the Nrf2/HO-1 pathway in MI/RI treatment.

Effect of electroacupuncture at Neiguan(PC6)at different time points on myocardial ischemia reperfusion arrhythmia in rats

OBJECTIVE:To observe the effects of electroacupuncture at Neiguan(PC6)at different time points on reperfusion arrhythmia(RA)after myocardial ischemia and reperfusion in rats,and to investigate the correlation of this protective effect with nerve growth factor(NGF),tyrosine kinase A(Trk A),tyrosine hydroxylase(TH),and norepinephrine(NE).METHODS:A total of 72 Sprague-Dawley male rats were randomly divided into six groups(n=12 rats/group):normal group(Norm),sham operation group(Sham),ischemia reperfusion group(I/R),pre-ischemic electroacupuncture group(EAI),pre-reperfusion electroacupuncture group(EAII),post-reperfusion electroacupuncture group(EAIII).The myocardial ischemia-reperfusion injury(MIRI)model was induced by occlusion of left anterior descending coronary artery for 20 min followed by reperfusion for 40 min in rats.With no intervention in the Norm group and only threading without ligation in the Sham group.Electroacupuncture pretreatment at 20 min/d for 7 d before ligation in the EAⅠgroup,20 min of electroacupuncture before reperfusion in the EAII group and 20 min of electroacupuncture after reperfusion in the EAIII group.The electrocardiogram(ECG)of each group was recorded throughout the whole process,and the success of the MIRI model was determined based on the changs of J-point and T-wave in the ECG.The arrhythmia score was used to record premature ventricular contractions,ventricular tachycardia and ventricular fibrillation during the reperfusion period to assess the reperfusion induced arrhythmias.The expression levels of NGF,Trk A,TH protein were measured by Western blot.Moreover,the expression levels of plasma and myocardial NE levels were detected by enzyme linked immunosorbent assay.RESULTS:The differences between Norm group and Sham group were not statistically significant in all indexes.Arrhythmia score,myocardial NGF,Trk A,TH,and NE expression were significantly higher in the I/R group compared with the Sham group.Arrhythmia score,myocardial NGF,Trk A,TH,and NE expression were significantly lower in each EA group compared with the I/R group.CONCLUSION:Electroacupuncture at Neiguan(PC6)at different time points can reduce the incidence and severity of reperfusion arrhythmias in rats.This protective effect is related to electroacupuncture regulating NGF,Trk A,TH,NE expression and reducing sympathetic hyperactivation.

Downregulation of cardiac PIASy inhibits Cx43 SUMOylation and ameliorates ventricular arrhythmias in a rat model of myocardial ischemia/reperfusion injury

Background:Dysfunction of the gap junction channel protein connexin 43(Cx43)contributes to myocardial ischemia/reperfusion(I/R)-induced ventricular arrhythmias.Cx43 can be regulated by small ubiquitin-like modifier(SUMO)modification.Protein inhibitor of activated STAT Y(PIASy)is an E3 SUMO ligase for its target proteins.However,whether Cx43 is a target protein of PIASy and whether Cx43 SUMOylation plays a role in I/R-induced arrhythmias are largely unknown.Methods:Male Sprague-Dawley rats were infected with PIASy short hairpin ribonucleic acid(shRNA)using recombinant adeno-associated virus subtype 9(rAAV9).Two weeks later,the rats were subjected to 45 min of left coronary artery occlusion followed by 2 h reperfusion.Electrocardiogram was recorded to assess arrhythmias.Rat ventricular tissues were collected for molecular biological measurements.Results:Following 45 min of ischemia,QRS duration and QTc intervals statistically significantly increased,but these values decreased after transfecting PIASy shRNA.PIASy downregulation ameliorated ventricular arrhythmias induced by myocardial I/R,as evidenced by the decreased incidence of ventricular tachycardia and ventricular fibrillation,and reduced arrythmia score.In addition,myocardial I/R statistically significantly induced PIASy expression and Cx43 SUMOylation,accompanied by reduced Cx43 phosphorylation and plakophilin 2(PKP2)expression.Moreover,PIASy downregulation remarkably reduced Cx43 SUMOylation,accompanied by increased Cx43 phosphorylation and PKP2 expression after I/R.Conclusion:PIASy downregulation inhibited Cx43 SUMOylation and increased PKP2 expression,thereby improving ventricular arrhythmias in ischemic/reperfused rats heart.

Role of Mitophagy in Myocardial Ischemia/Reperfusion Injury and Chinese Medicine Treatment

Mitophagy is one of the important targets for the prevention and treatment of myocardial ischemia/reperfusion injury(MIRI).Moderate mitophagy can remove damaged mitochondria,inhibit excessive reactive oxygen species accumulation,and protect mitochondria from damage.However,excessive enhancement of mitophagy greatly reduces adenosine triphosphate production and energy supply for cell survival,and aggravates cell death.How dysfunctional mitochondria are selectively recognized and engulfed is related to the interaction of adaptors on the mitochondrial membrane,which mainly include phosphatase and tensin homolog deleted on chromosome ten(PTEN)-induced kinase 1/Parkin,hypoxia-inducible factor-1α/Bcl-2 and adenovirus e1b19k Da interacting protein 3,FUN-14 domain containing protein 1 receptor-mediated mitophagy pathway and so on.In this review,the authors briefly summarize the main pathways currently studied on mitophagy and the relationship between mitophagy and MIRI,and incorporate and analyze research data on prevention and treatment of MIRI with Chinese medicine,thereby provide relevant theoretical basis and treatment ideas for clinical prevention of MIRI.

Potential relationship between autophagy and ferroptosis in myocardial ischemia/reperfusion injury

Autophagy is an evolutionarily conserved process involved in the degradation of long-lived proteins and excessive or dysfunctional organelles. As a pivotal cellular response, autophagy has been extensively studied and is known to be involved in various diseases. Ferroptosis is a recently discovered form of regulated cell death characterized by iron overload, leading to the accumulation of lethal levels of lipid hydroperoxides. Recently, an increasing number of studies have revealed a link between autophagy and ferroptosis. Myocardial ischemia/reperfusion injury (MIRI) is an urgent dilemma after myocardial infarction recanalization, which is regulated by several cell death pathways, including autophagy and ferroptosis. However, the potential relationship between autophagy and ferroptosis in MIRI remains unexplored. In this study, we briefly review the mechanisms of autophagy and ferroptosis, including their roles in MIRI. Moreover, we provide an overview of the potential crosstalk in MIRI. Clarifying the relationship between different cell death pathways may provide new ideas for the treatment of MIRI in the future.

MicroRNA-208a silencing against myocardial ischemia/reperfusion injury mediated by reversibly camouflaged biomimetic nanocomplexes

MicroRNA-208a(miR-208a)plays critical roles in the severe fibrosis and heart failure post myocardial ischemia/reperfusion(IR)injury.MiR-208a inhibitor(mI)with complementary RNA sequence can silence the expression of miR-208a,while it is challenging to achieve efficient and myocardium-targeted delivery.Herein,biomimetic nanocomplexes(NCs)reversibly coated with red blood cell membrane(RM)were developed for the myocardial delivery of mI.To construct the NCs,membrane-penetrating helical polypeptide(PG)was first adopted to condense mI and form the cationic inner core,which subsequently adsorbed catalase(CAT)via electrostatic interaction followed by surface coating with RM.The membrane-coated NCs enabled prolonged blood circulation after systemic administration,and could accumulate in the injured myocardium via passive targeting.In the oxidative microenvironment of injured myocardium,CAT decomposed H_(2)O_(2)to produce O_(2)bubbles,which drove the shedding of the outer RM to expose the positively charged inner core,thus facilitated effective internalization by cardiac cells.Based on the combined contribution of mI-mediated miR-208a silencing and CAT-mediated alleviation of oxidative stress,NCs effectively ameliorated the myocardial microenvironment,hence reducing the infarct size as well as fibrosis and promoting recovery of cardiac functions.This study provides an effective strategy for the cytosolic delivery of nucleic acid cargoes in the myocardium,and it renders an enlightened approach to resolve the blood circulation/cell internalization dilemma of cell membrane-coated delivery systems.

N-acetylcysteine attenuates ischemia/reperfusion-induced cardiocyte apoptosis in diabetic rats

Objective：To study the effects of N-acetylcysteine （NAC） on ischemia/ reperfusion （I/R）-induced myocyte apoptosis in diabetic rats. Methods：The I/R heart model was made by ligation of the left anterior descending coronary artery （LAD） close to its origin. The LAD was occluded for 30 min followed by removal of ligation to allow subsequent reperfusion for 3 h. 72 rats were randomly divided into two groups , non-diabetic group （C, n = 36） and diabetic group ,（D, n = 36）. The animals in C group were randomly reassigned into sham-operated group （CS, n = 12） , I/R group （C I/R, n = 12） and treated with NAC group （CN, n = 12）. The rats in D group were also reassigned to sham-operated group （DS, n = 12） , I/R group （DI/R, n = 12） and treated with NAC group （DN, n = 12）. Malondialdehyde （MDA） and creatine kinase isoenzyme-MB （CK-MB） were measured. Infarct size（IS/AAR%）, the apoptosis index（AI） by TUNEL staining, the number of the cells positive for Caspase-3 and positive expression index （PEI） were calculated. Results：After I/R, the IS/AAR%, CK-MB, MDA, AI and Caspase-3 PEI were higher in diabetic group than those in non-diabetic group. Treatment with NAC decreased the above parameters in both non-diabetic and diabetic rats, but the parameters in diabetic rats were higher than those in non-diabetic rats. Conclusion：Diabetic rat hearts are more susceptible to I/R-induced myocardial necrosis and myocyte apoptosis. NAC can decrease the infarct size and attenuate cardiomyocyte apoptosis in both non-diabetic and diabetic rats, but the therapeutic effects are less effective in diabetic rats than those in non-diabetic rats.