三七皂苷R1通过调控ALOX15/PEBP1信号通路抑制氧化应激而减轻大鼠心肌缺血再灌注损伤OA

AIM:To investigate the protective effect of notoginsenoside R1(NGR1)against myocardial isch-emia-reperfusion injury(MIRI)in rats and its underlying molecular mechanism,with a focus on the regulation of oxidative stress mediated by the ALOX15/PEBP1 signaling pathway.METHODS:Twenty-four specific pathogen-free male Sprague-Dawley rats were randomly divided into four groups(n=6 per group):sham,MIRI model(MIRI),MIRI+low-dose NGR1(25 mg/kg),and MIRI+high-dose NGR1(50 mg/kg)groups.The NGR1 or vehicle was administered intragas-trically for 7 consecutive days prior to surgery.The MIRI model was established via left anterior descending coronary artery ligation for 45 min followed by 2 h of reperfusion,and successful modeling was confirmed by electrocardiographic monitoring.Myocardial injury was assessed by 2,3,5-triphenyltetrazolium chloride(TTC)staining,hematoxylin and eosin(HE)staining,and determination of the serum levels of lactate dehydrogenase(LDH)and cardiac troponin I(cTnI).The levels of oxidative stress indicators,including malondialdehyde(MDA)and superoxide dismutase(SOD),were measured.Re-active oxygen species(ROS)levels in myocardial tissues were detected using a dihydroethidium(DHE)fluorescence probe.Network pharmacology and molecular docking analyses were performed to identify the core targets and pathways through which NGR1 acts against MIRI.In vitro,H9C2 cardiomyocytes were subjected to hypoxia/reoxygenation(H/R)to mimic MIRI and were treated with NGR1(20 μmol/L)or trimetazidine.Cell viability was assessed by a CCK-8 assay,and cell injury was evaluated by LDH release.Cell morphology was observed by phalloidin staining,intracellular ROS levels were detected using a DCFH-DA probe,and mitochondrial function was assessed by JC-1 and mitochondrial permeability transition pore(MPTP)staining.The protein expression levels of arachidonate 15-lipoxygenase(ALOX15)and phosphati-dylethanolamine-binding protein 1(PEBP1)in rat myocardial tissue and H9C2 cells were determined by Western blot.RESULTS:Compared with the changes in the MIRI group,the myocardial infarct size was significantly reduced,the se-rum LDH,cTnI,and MDA levels were decreased,the SOD activity was increased;ROS production in myocardial tissues was reduced,and the protein expressions of ALOX15 and PEBP1 were downregulated in the NGR1 pretreatment group in vivo(P<0.05).Network pharmacology revealed that oxidative stress is a core biological process involved in the anti-MIRI effect of NGR1.In vitro,compared with H/R treatment,NGR1(20 μmol/L)treatment resulted in a significant increase in H9C2 cell viability,alleviation of cell injury,enhancement of mitochondrial function,reduction in intracellular ROS levels,and downregulation of ALOX15 and PEBP1 protein expressions(P<0.05).CONCLUSION:The NGR1 protects against MIRI-and H/R-induced cardiomyocyte injury by inhibiting ALOX15/PEBP1 signaling,alleviating oxidative stress,and enhancing mitochondrial function.