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.

BH3-only protein Bim is involved in myocardial injury induced by co-stress of ischemia and cold stress in rats

Objectives To investigate the effect of co-exposure of myocardial ischemia and cold stress on myocardial injury in rats and the relative mechanism.Methods Myocardial ischemia model was established by ligation of left coronary artery.SD rats were randomly allocated to 4 groups; sham+normal temperature(S group),sham+cold stress(SC group),myocardial ischemia+ normal temperature(Ⅰgroup), myocardial ischemia+cold stress(IC group).On the condition of 26℃,SC and IC groups were keeped in a 4℃artificial chamber for 8h(8;00-16:00) for 4 consecu- tive days.Car diac function was assessed by echocardiography;pathological change was analyzed by HE staining;myocardial infarct size was determined by TTC staining;Bim,Caspase-3 expression in myocardium was determined by western blotting.Results It was demonstrated that co-exposure of myocardial ischemia and cold stress could significantly make the cardiac muscle in abnormal shape,increase the infarct size and the expression of Bim and Caspase-3.Conclusions Co-exposure of myocardial ischemia and cold stress may aggravate the cardiac injury,pro- apoptosis protein Bim is involved.

Antioxidative effect of peroxiredoxin-3 in the rat myocardium exposed to renal ischemia-reperfusion injury

Background:Peroxiredoxin-3(Prx-3)is known to be involved in the clearance of cellular hydrogen peroxide and plays an important role in protecting the myocardial tissue against damage of oxidative stress.However,the role of Prx-3 in protecting the myocardial tissue against renal ischemia/reperfusion(I/R)-induced myocardial injury(RI/RMI)remains unknown.We aimed to examine the antioxidative effect of Prx-3 using a rat RI/RMI model in an attempt to find a new approach to the prevention and treatment of myocardial injury induced by renal I/R.Methods:A RI/RMI rat model was established to detect the renal histopathology and renal functions by hematoxylin-eosin staining staining and commercially available assay kits.The myocardial antioxidant activity and the expressions of mRNA and protein of Prx-3 in the myocardial tissue were measured by real-time polymerase chain reaction and Western blotting assay,respectively.Results:Compared with the normal and control groups,the serum level of blood urea nitrogen and serum creatinine was significantly increased in the I/R group(P<0.05).Histopathological changes in the kidneys were also more obvious,including glomerular cystic and renal interstitial hemorrhage,renal tubular epithelial cell edema,and tubular type formation.The mRNA and protein expressions of Prx-3 were increased significantly in the RI/MRI rat model as compared with those in the normal and control groups.Conclusion:Oxidative damage occurred in the remote myocardium after renal I/R and Prx-3 was able to enhance the self-regulatory ability of the myocardium against damage from oxidative stress after RI/MRI.

Progresses in the research of Danhong Injection against the cardial ischemia-referfusion injury

Researches in the field of the myocardial ischemia-reperfusion injury are attracting the attentions of clinicians for the treatments that protect cardiac muscle cells from being injured can not only help the patients get recovery but also keep them in health. By clearing the free radicals and reducing calcium overload of myocardial cell, treatments with Danhong Injection will help myocardial cells survive from inflammatory reactions which are triggered by ischemia reperfusion so as that endothelial function will be improved and myocardial cell apoptosis will be inhibited. In all, Danhong Injection is an ideal medicine for protecting myocardial cell against ischemia reperfusion injury.

Study of 7-Hydroxyflavone against Oxidative Stress in Myocardial Ischemia/Reperfusion Injury Based on Network Pharmacology and Bioinformatics

Subjective: This study aimed to investigate the therapeutic mechanisms of 7-hydroxyflavone (7-HF) in treating myocardial ischemia/reperfusion injury (MI/RI) via network pharmacology, molecular docking, target validation, and experiments at the animal level. Methods: Firstly, the genes of 7-HF were acquired from PharmMapper, TCMSP, and SwissTargetPrediction. At the same time, MI/RI-related genes were obtained from OMIM, GeneCards, and TTD online platforms. Subsequently, string platform and Cytoscape 3.9.2 were used to construct protein-protein interaction network diagrams and 7-HF-targets-signaling pathways-MI/RI network. Then, the Metascape platform was used to conduct functional enrichment analyses. Next, AutoDock Vina and Pymol were used to perform molecular docking. The hub targets were validated in the GSE66360. Lastly, SOD, MDA, transmission electron microscope, quantitative real-time PCR, and western blot were used to validate in MI/RI rats. Results: 139 genes of 7-HF, 4832 genes of MI/RI were obtained. The 47 interact genes between 7-HF and MI/RI targets for MI/RI were likely to act through multiple pathways. And NQO1 was a critical target in the above process. In an animal experiment, 7-HF could relieve the injured interfibrillar mitochondria and myocardial fibers, decrease the expression of MDA and SOD, and increase the expression of Nrf2, NQO1 and HO-1 in the mRNA and protein level in the MI/RI rats. Conclusion: This study preliminarily demonstrated that 7-HF could provide cardioprotection by inhibiting the oxidative stress and up-regulating Nrf2/NQO1/HO-1 signaling pathway based on network pharmacology, molecular docking, target validation, and animal experiments.

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.

Luteolin protects against myocardial ischemia/reperfusion injury by reducing oxidative stress and apoptosis through the p53 pathway

Objective:Myocardial ischemia/reperfusion injury(MIRI)is an obstacle to the success of cardiac reperfusion therapy.This study explores whether luteolin can mitigate MIRI by regulating the p53 signaling pathway.Methods:Model mice were subjected to a temporary surgical ligation of the left anterior descending coronary artery,and administered luteolin.The myocardial infarct size,myocardial enzyme levels,and cardiac function were measured.Latent targets and signaling pathways were screened using network pharmacology and molecular docking.Then,proteins related to the p53 signaling pathway,apoptosis and oxidative stress were measured.Hypoxia/reoxygenation(HR)-incubated HL1 cells were used to validate the effects of luteolin in vitro.In addition,a p53 agonist and an inhibitor were used to investigate the mechanism.Results:Luteolin reduced the myocardial infarcted size and myocardial enzymes,and restored cardiac function in MIRI mice.Network pharmacology identified p53 as a hub target.The bioinformatic analyses showed that luteolin had anti-apoptotic and anti-oxidative properties.Additionally,luteolin halted the activation of p53,and prevented both apoptosis and oxidative stress in myocardial tissue in vivo.Furthermore,luteolin inhibited cell apoptosis,JC-1 monomer formation,and reactive oxygen species elevation in HR-incubated HL1 cells in vitro.Finally,the p53 agonist NSC319726 downregulated the protective attributes of luteolin in the MIRI mouse model,and both luteolin and the p53 inhibitor pifithrin-a demonstrated a similar therapeutic effect in the MIRI mice.Conclusion:Luteolin effectively treats MIRI and may ameliorate myocardial damage by regulating apoptosis and oxidative stress through its targeting of the p53 signaling pathway.Please cite this article as:Zhai P,Ouyang XH,Yang ML,Lin L,Li JY,Li YM,Cheng X,Zhu R,Hu DS.Luteolin protects against myocardial ischemia/reperfusion injury by reducing oxidative stress and apoptosis through the p53 pathway.J Integr Med.2024;22(6):652–664.

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.

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

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

Shenmai Injection Attenuates Myocardial Ischemia/Reperfusion Injury by Targeting Nrf2/GPX4 Signalling-Mediated Ferroptosis

Objective:To examine the effect of Shenmai Injection(SMJ)on ferroptosis during myocardial ischemia reperfusion(I/R)injury in rats and the underlying mechanism.Methods:A total of 120SPF-grade adult male SD rats,weighing 220–250 g were randomly divided into different groups according to a random number table.Myocardial I/R model was established by occluding the left anterior descending artery for 30 min followed by 120 min of reperfusion.SMJ was injected intraperitoneally at the onset of 120 min of reperfusion,and erastin(an agonist of ferroptosis),ferrostatin-1(Fer-1,an inhibitor of ferroptosis)and ML385(an inhibitor of nuclear factor erythroid-2 related factor 2(Nrf2))were administered intraperitoneally separately 30 min before myocardial ischemia as different pretreatments.Cardiac function before ischemia,after ischemia and after reperfusion was analysed.Pathological changes in the myocardium and the ultrastructure of cardiomyocytes were observed,and the myocardial infarction area was measured.Additionally,the concentration of Fein heart tissues and the levels of creatine kinase-MB(CK-MB),troponin I(cTnI),malondialdehyde(MDA)and superoxide dismutase(SOD)in serum were measured using assay kits,and the expressions of Nrf2,glutathione peroxidase 4(GPX4)and acyl-CoA synthetase long-chain family member 4(ACSL4)were examined by Western blot.Results:Compared with the sham group,I/R significantly injured heart tissues,as evidenced by the disordered,ruptured and oedematous myocardial fibres;the increases in infarct size,serum CK-MB,cTnI and MDA levels,and myocardial Feconcentrations;and the decreases in SOD activity(P<0.05).These results were accompanied by ultrastructural alterations to the mitochondria,increased expression of ACSL4 and inhibited the activation of Nrf2/GPX4 signalling(P<0.05).Compared with the I/R group,pretreatment with 9 mL/kg SMJ and 2 mg/kg Fer-1 significantly reduced myocardial I/R injury,Feconcentrations and ACSL4 expression and attenuated mitochondrial impairment,while 14 mg/kg erastin exacerbated myocardial I/R injury(P<0.05).In addition,cardioprotection provided by 9 mL/kg SMJ was completely reversed by ML385,as evidenced by the increased myocardial infarct size,CK-MB,cTnI,MDA and Feconcentrations,and the decreased SOD activity(P<0.05).Conclusions:Ferroptosis is involved in myocardial I/R injury.Pretreatment with SMJ alleviated myocardial I/R injury by activating Nrf2/GPX4 signalling-mediated ferroptosis,thereby providing a strategy for the prevention and treatment of ischemic heart diseases.

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.

Protective Mechanisms of Suxiao Jiuxin Pills(速效救心丸) on Myocardial Ischemia-Reperfusion Injury in vivo and in vitro

Objective:To study the protective mechanism of Chinese medicine Suxiao Jiuxin Pills(速效救心丸,SXJ)on myocardial ischemia and reperfusion(I/R)injury.Methods:Mouse myocardial I/R injury model was created by 30-min coronary artery occlusion followed by 24-h reperfusion,the mice were then divided into the sham group(n=7),the I/R group(n=13),the tirofiban group(TIR,positive drug treatment,n=9),and the SXJ group(n=11).Infarct size(IS),risk region(RR),and left ventricle(LV)were analyzed with double staining methods.In addition,H9C2 rat cardiomyocytes were cultured with Na2S2O4 to simulate I/R in vitro.The phosphorylation of extracellular regulated protein kinases1/2(ERK1/2),protein kinase B(AKT),glycogen synthase kinase-3β(GSK3β),and protein expression of GATA4 in nucleus were detected with Western blot assay.Results:The ratio of IS/RR in SXJ and TIR groups were lower than that in I/R group(SXJ,22.4%±6.6%;TIR,20.8%±3.3%;vs.I/R,35.4%±3.7%,P<0.05,respectively).In vitro experiments showed that SXJ increased the Na2S2O4-enhanced phosphorylation of AKT/GSK3βand nuclear expression of GATA4.Conclusion:SXJ prevents myocardial I/R injury in mice by activating AKT/GSK3βand GATA4 signaling pathways.

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.

Cardiomyocyte-targeted anti-inflammatory nanotherapeutics against myocardial ischemia reperfusion (IR) injury

Myocardial ischemia reperfusion(IR)injury is closely related to the overwhelming inflammation in the myocardium.Herein,cardiomyocyte-targeted nanotherapeutics were developed for the reactive oxygen species(ROS)-ultrasensitive co-delivery of dexamethasone(Dex)and RAGE small interfering RNA(siRAGE)to attenuate myocardial inflammation.PPTP,a ROSdegradable polycation based on PGE2-modified,PEGylated,ditellurium-crosslinked polyethylenimine(PEI)was developed to surface-decorate the Dex-encapsulated mesoporous silica nanoparticles(MSNs),which simultaneously condensed siRAGE and gated the MSNs to prevent the Dex pre-leakage.Upon intravenous injection to IR-injured rats,the nanotherapeutics could be efficiently transported into the inflamed cardiomyocytes via PGE2-assisted recognition of over-expressed E-series of prostaglandin(EP)receptors on the cell membranes.Intracellularly,the over-produced ROS degraded PPTP into small segments,promoting the release of siRAGE and Dex to mediate effective RAGE silencing(72%)and cooperative antiinflammatory effect.As a consequence,the nanotherapeutics notably suppressed the myocardial fibrosis and apoptosis,ultimately recovering the systolic function.Therefore,the current nanotherapeutics represent an effective example for the codelivery and on-demand release of nucleic acid and chemodrug payloads,and might find promising utilities toward the synergistic management of myocardial inflammation.

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.

The protective effect of ginsenoside Rb1 pre-treatment on myocardial ischemia/reperfusion injury in Sprague-Dawley rats

Background Myocardial ischemia/reperfusion injury(MI/RI)during myocardial infarction worsens outcomes. It has been proved that ginsenoside Rb1 has a great impact on ischemia/reperfusion(I/R)injury. The aim of this study is to explore the protective effect of the pretreatment with ginsenoside Rb1 on MI/RI and investigate the underlying mechanisms about the preventive action. Methods A total of 27 healthy adult Sprague-Dawley(SD)rats were randomly divided into 3 groups(n=9 per group):A sham-operated group(Sham n=9);an ischemia 40 min/reperfusion 2 h(I/R n=9)of the cardiac muscle group;Rb1-treated group was divided into 3 subgroups(Rb1 10 mg/kg,20 mg/kg,40 mg/kg,n=3). Ginsenosides Rb1 at different concentrations were injected intraperitoneally for 3 days continuously before ligation. A model of MI/RI was constructed by ligation of the left coronary artery anterior descending branch in rats. Myocardial infarction area after I/R was measured bytriphenyltetrazolium chloride(TTC)staining of myocardial tissue. Hematoxylin and eosin(HE)staining and electrocardiogram indication were used to observe myocardial cell injury and ischemia,respectively. The expression of caspase-8 protein was observed by immunohistochemistry staining. Results The pretreatment of 40 mg/kg dose of ginsenoside Rb1 could decrease the expression of caspase-8 protein caused by I/R and the apoptosis of myocardial cells,improve myocardial ischemia,reduce the area of myocardial infarction and ameliorate MI/RI.Conclusions These results demonstrate that ginsenoside Rb1 has a significant protective effect on MI/RI through attenuating the apoptosis of myocardial cells and improving myocardial ischemia at appropriate dose,which provides new insights into the potential therapy of MI/RI.