线粒体H_(2)S供体AP39对心肌梗死大鼠心肌纤维化的影响及其与线粒体动力学的关系

Effect of the mitochondrial H_(2)S donor AP39 on myocardial fibrosis in rats with myocardial infarction and its relationship to mitochondrial dynamics

[目的]已有研究表明H_(2)S可拮抗心肌纤维化,但线粒体靶向性H_(2)S能否拮抗心肌梗死后心肌纤维化,且是否与调控线粒体融合与分裂有关目前并不明确。为了探究这一关系,进行了该研究。[方法]在动物实验中予以异丙肾上腺素[ISO,50 mg/(kg·d)]腹腔注射构建SD大鼠心肌梗死模型,对各组大鼠行心电图检测,使用线粒体H_(2)S供体AP39[36μg/(kg·d)],腹腔注射连续处理SD大鼠4周,使用Masson染色检测心肌纤维化情况,使用Western blot检测相关蛋白表达情况。体外实验以氯化钴(CoCl_(2),800μmol/L)诱导H9c2心肌细胞缺氧损伤,AP39(100 nmol/L)处理H9c2细胞,使用DL-炔丙基甘氨酸(PAG,2 mmol/L)抑制内源性硫化氢合成酶胱硫醚-γ-裂解酶(CSE),并通过荧光探针检测心肌细胞活性氧(ROS)的水平。[结果]梗死大鼠心肌存在明显间质纤维化,胶原纤维大量堆积,且CSE、线粒体融合蛋白2(MFN2)表达下调,线粒体动力相关蛋白1(DRP1)表达增加,AP39干预后则可明显改善以上变化,而加入CSE抑制剂PAG则可逆转AP39的以上作用。同时在体外实验中发现,以CoCl_(2)诱导H9c2心肌细胞缺氧损伤时,细胞内ROS水平升高,MFN2表达下调,DRP1表达增加,AP39则可上调MFN2蛋白表达,抑制DRP1表达,降低心肌细胞ROS水平,而PAG则可逆转以上变化。[结论]线粒体靶向性H_(2)S供体AP39可以改善心肌梗死大鼠心肌纤维化,且可促进线粒体融合,抑制线粒体过度分裂。

Aim Previous studies have indicated that H_(2)S can attenuate myocardial fibrosis.However,it is unclear whether mitochondria-targeted H_(2)S can attenuate myocardial fibrosis after myocardial infarction and whether its mechanism is associated with the regulation of mitochondrial fusion and fission.To investigate this relationship,this study was conducted.Methods Isoproterenol(ISO,50 mg/(kg·d))was injected intraperitoneally to induce myocardial infarction in SD rats.Electrocardiograms were performed on each group of rats,and the rats were treated with AP39(36μg/(kg·d),intraperitoneal)for 4 weeks.Masson's staining was used to assess the extent of myocardial fibrosis.Western blot was used to measure the expression of relevant proteins.In vitro experiments were performed to induce hypoxic injury in H9c2 cardiomyocytes with CoCl_(2)(800μmol/L),H9c2 cells were treated with AP39(100 nmol/L),and the endogenous hydrogen sulfide synthase cystathionine-γ-lyase(CSE)was inhibited using DL-propargylglycine(PAG,2 mmol/L),and fluorescence probe was used to measure the level of reactive oxygen species(ROS)in myocardial cells.Results Myocardial fibrosis was evident in infarcted rat hearts,with a significant accumulation of collagen fibers.Additionally,the expression of CSE and mitofusin 2(MFN2)proteins was downregulated,while dynamin-related protein 1(DRP1)protein expression was increased.Intervention with AP39 significantly improved the above changes,and the addition of CSE inhibitor PAG reversed the effects of AP39.In in vitro experiments,when H9c2 myocardial cells were subjected to hypoxic injury induced by CoCl_(2),intracellular ROS levels increased,MFN2 expression was downregulated,and DRP1 expression was upregulated.AP39 upregulated MFN2 protein expression,inhibited DRP1 protein expression,and reduced ROS levels in myocardial cells.The addition of PAG reversed these changes.Conclusion The mitochondria-targeted H_(2)S donor,AP39,can improve myocardial fibrosis in rats with myocardial infarction and promote mitochondrial fusion and inhibit excessive mitochondrial division.