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.

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.

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.

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.

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.

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.

Reactive oxygen species-based nanomaterials for the treatment of myocardial ischemia reperfusion injuries

Interventional coronary reperfusion strategies are widely adopted to treat acute myocardial infarction,but morbidity and mortality of acute myocardial infarction are still high.Reperfusion injuries are inevitable due to the generation of reactive oxygen species(ROS)and apoptosis of cardiac muscle cells.However,many antioxidant and anti-inflammatory drugs are largely limited by pharmacokinetics and route of administration,such as short half-life,low stability,low bioavailability,and side effects for treatment myocardial ischemia reperfusion injury.Therefore,it is necessary to develop effective drugs and technologies to address this issue.Fortunately,nanotherapies have demonstrated great opportunities for treating myocardial ischemia reperfusion injury.Compared with traditional drugs,nanodrugs can effectively increase the therapeutic effect and reduces side effects by improving pharmacokinetic and pharmacodynamic properties due to nanodrugs’size,shape,and material characteristics.In this review,the biology of ROS and molecular mechanisms of myocardial ischemia reperfusion injury are discussed.Furthermore,we summarized the applications of ROS-based nanoparticles,highlighting the latest achievements of nanotechnology researches for the treatment of myocardial ischemia reperfusion injury.

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.

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

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

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.

Activation of epidermal growth factor receptor mediates myocardial ischemia/reperfusion arrhythmias in anaesthetized rats

Objectives Epidermal growth factor receptor （EGFR）is a receptor protein tyrosine kinase and plays a critical role in the development and function of the heart.Previous studies have demonstrated that EGFR is involved in regulating electrical excitability of the heart.The present study was designed to investigate whether EGFR activation would mediate myocardial arrhythmias induced by ischemia/reperfu- sion in anaesthetized rats.Methods and results Myocardial ischemia/reperfusion arrhythmias were induced by 10 min ligation of the left anterior descending coronary artery,followed by a 30 min reperfusion in anaesthetized rats.Incidence and severity of cardiac arrhythmias were significantly reduced by pretreatment with the EGFR kinase inhibitor AG556.Phosphorylation level of myocardial EGFR was increased during ischemia and at early reperfusion.Intramyocardial transfection of EGFR siRNA reduced EGFR mRNA and protein,and decreased the incidence of ventricular fibrillation induced by reperfusion.Interestingly,tyrosine phosphorylation levels of cardiac Na+ channel(INa) and L-type Ca2+ channel(ICa.l) were significantly increased at corresponding time points to the alteration of phosphorylated EGFR level during reperfusion.AG556 pretreatment countered the increased tyrosine phosphorylation level of Na+ and L-type Ca2+ channels induced by reperfusion.No significant alteration was observed in tyrosine phosphorylation levels of cardiac Kv4.2 and Kir2.1 channels during the cardiac ischemia/reperfusion. Conclusions These results demonstrate for the first time that EGFR plays an important role in the genesis of myocardial ischemia/reperfusion arrhythmias,which is likely mediated at least in part by enhancing tyrosine phosphorylation of cardiac Na+ and L-type Ca2+ channels.

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.

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.

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.

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.

Methylprednisolone improves microcirculation in streptozotocin-induced diabetic rats after myocardial ischemia/reperfusion

Background Methylprednisolone has been demonstrated to decrease inflammation, and it may protect organs from ischemia/reperfusion （I/R） injury. This study aimed to investigate the effects of methylprednisolone on diabetic myocardial I/R injury.Methods Forty adult male Sprague-Dawley （SD） rats were randomized into five groups （n=8 in each group） including a sham operation （sham） group, I/R group, diabetic sham operation （DMS） group, diabetic I/R （DM-I/R） group and methylprednisolone intervention （MP＋DM-I/R） group. The diabetic model was produced by injection of streptozotocin （STZ）. Body weight and blood glucose levels were determined after diabetes was established. Twelve weeks after induction of diabetes, a segmental I/R of the heart was induced by occluding the left anterior descending artery for one hour and then three hours of reperfusion in the I/R, DM-I/R and MP＋DM-I/R groups. Blood pressure and electrocardiogram were continuously recorded during the procedure. IL-1β, IL-6 and TNF-α were measured at certain time points during the surgery. After reperfusion, a microcirculation scan was performed; myocardial biomarkers and tissue structure were utilized to evaluate the reperfusion damage. Intercellular adhesion molecule （ICAM）-1 and NF-κBp65 expression were quantified by immunohistological staining. Total Toil-like receptor 4 （TLR4） and nuclear NF-κBp65 protein were determined by Western blotting.Results Twelve weeks after diabetes was established, blood glucose levels were elevated and body weights were lower in diabetic rats. After reperfusion, infarction size was increased, myocardial biomarkers and inflammatory cytokines levels were elevated. Microcirculation perfusion was significantly reduced in the DM-I/R group compared with the I/R group, however it was improved in the MP＋DM-I/R group. The expression of NF-κBp65 and ICAM-1 were increased in the DM-I/R group and decreased in the MP＋DM-I/R group, Compared with the non-diabetic I/R group, TLR4 and NF-κBp65 protein levels were up-regulated in the DM-I/R group, but down-regulated in the MP＋DM-I/R group.Conclusions Methylprednisolone improves microcirculation in STZ-induced diabetic rats after myocardial ischemia/reperfusion, which may associate with the suppression of TLR4/NF-κB signaling.