多肽CRY-14保护心肌对抗缺血缺氧损伤的作用机制

Study on the mechanism of peptide CRY-14 in protecting myocardium against hypoxic-ischemic injury

目的研究多肽CRY-14在心肌缺血缺氧中的作用与机制。方法分析多肽CRY-14对缺血缺氧后H9C2心肌细胞增殖、氧化应激的影响。通过M型小动物心超比较多肽CRY-14对小鼠心肌梗死后心脏功能[左心室舒张末内径(LVEDD)、左心室收缩末内径(LVESD)、左心室射血分数(LVEF)及左心室缩短分数(LVFS)]的影响。小鼠心脏组织HE染色、Tunel染色以及Masson染色评估多肽CRY-14干预后小鼠心肌梗死后心脏组织学及凋亡的变化。此外,Western Blot实验初步探讨多肽CRY-14发挥心肌保护功能的机制。结果在细胞水平,多肽CRY-14可以缓解缺血缺氧对H9C2心肌细胞增殖的抑制作用,减轻缺血缺氧导致的氧化应激反应。在体水平,CRY-14可以缓解小鼠心肌梗死后心功能的改变,提高LVEF、LVFS,降低LVEDD、LVESD。CRY-14可以明显改善小鼠心肌梗死后心肌损伤,减轻心肌细胞凋亡以及心肌纤维化程度。此外,Western Blot结果提示CRY-14可以下调缺血缺氧后H9C2心肌细胞凋亡相关蛋白Caspase 3以及PARP的表达,CRY-14可以上调缺血缺氧后H9C2心肌细胞HSP70的表达。结论多肽CRY-14可通过改善缺血性心脏病中的氧化应激和凋亡水平发挥心肌保护作用,其机制可能与调控HSP70有关。

Objective To explore the role and mechanism of peptide CRY-14 in myocardial ischemia and hypoxia.Methods The effects of peptide CRY-14 on the proliferation and oxidative stress of H9C2 myocardial cells after ischemia and hypoxia was analyzed.The effects of peptide CRY-14 on cardiac function(LVEF,LVFS,LVEDD,LVESD)were compared after myocardial infarction in mice by M-type small animal heart ultrasound.HE staining,Tunel staining and Masson staining were used to evaluate the changes of cardiac histology and apoptosis after the intervention of CRY-14.In addition,Western Blot assay was used to investigate the mechanism of myocardial protection of peptide CRY-14.Results At the cellular level,CRY-14 alleviated the inhibitory effect of ischemia and hypoxia on the proliferation of H9C2 cardiomyocytes,and reduced the oxidative stress response caused by ischemia and hypoxia.In vivo,CRY-14 alleviated the changes of cardiac function after myocardial infarction,increase LVEF and LVFS,and decrease LVEDD and LVESD.CRY-14 improved significantly myocardial injury,reduced myocardial cell apoptosis and myocardial fibrosis in mice after myocardial infarction.In addition,Western blot results suggested that CRY-14 can downregulate the expression of apoptosis related protein Caspase 3 and PARP in H9C2 cardiomyocytes after ischemia and hypoxia,while CRY-14 upregulated the expression of HSP70 in H9C2 cardiomyocytes after ischemia and hypoxia.Conclusions Peptide CRY-14 plays a myocardial protective role by improving oxidative stress and apoptosis levels in ischemic heart disease,and its mechanism may be related to the regulation of HSP70.