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目的:探讨运动性心肌损伤中大鼠缝隙连接蛋白43(Cx43)基因和蛋白表达的变化。方法:SD大鼠50只随机分为对照组(C组)和力竭运动组(EE组),大强度力竭跑台运动建立运动性心肌损伤模型。用苏木素-碱性品红-苦味酸(HBFP)染色方法观察大鼠心肌缺血缺氧改变,心肌肌钙蛋白I(cTnI)含量用免疫化学发光法进行检测,心肌Cx43 mRNA的表达分布采用原位杂交方法,用实时荧光定量PCR法检测心肌Cx43 mRNA表达,用免疫组织化学方法观察心肌Cx43表达分布,用Western免疫印迹法检测Cx43蛋白表达。结果:与C组相比,EE组心肌缺血缺氧面积明显增加,血清cTnI含量明显升高,Cx43原位杂交信号有减弱趋势,免疫阳性反应明显减弱,可见少量Cx43免疫阳性分布于心肌细胞闰盘和侧对侧连接处,Cx43蛋白表达水平明显降低。结论:1)大强度力竭运动导致大鼠运动性心肌损伤,该损伤能引起心肌Cx43分布模式的改变,提示心肌Cx43是导致心功能异常并引发运动性心肌损伤的结构基础。2)心肌Cx43蛋白表达在运动性心肌损伤中降低,提示力竭运动可能通过引起Cx43去磷酸化而引起Cx43表达降低,从而导致运动性心肌损伤的发生。
Objective: To investigate the changes of the gene and protein expression of connexin 43 (Cx43) in rats with exercise-induced myocardial injury. Methods: Fifty SD rats were randomly divided into control group (C group) and exhaustive exercise group (EE group). The model of exercise-induced myocardial injury was established by intensive exhaustive treadmill exercise. The changes of myocardial ischemia and hypoxia were observed by hematoxylin-eosin-basic fuchsin-picric acid (HBFP) staining. The content of cardiac troponin I (cTnI) was detected by immunochemical chemiluminescence. The hybridization method was used to detect the expression of Cx43 mRNA in myocardium by real-time fluorescence quantitative PCR. The expression of Cx43 in myocardium was observed by immunohistochemical method. The expression of Cx43 protein was detected by Western blotting. Results Compared with group C, the area of myocardial ischemia and hypoxia in EE group was significantly increased, the content of cTnI in serum was significantly increased, the signal of Cx43 in situ hybridization was weakened, and the immunoreactivity was significantly decreased, showing that a small amount of Cx43 immunoreactively distributed in myocardial cells Intercalated disc and side to side connections, Cx43 protein expression was significantly reduced. Conclusion: 1) Excessive exhaustive exercise leads to exercise-induced myocardial injury in rats, which can cause changes in myocardial Cx43 distribution pattern, suggesting that myocardial Cx43 is the structural basis of cardiac dysfunction and motor myocardium injury. 2) Myocardial Cx43 protein expression in exercise-induced myocardial injury decreased, suggesting that exhaustive exercise may lead to Cx43 dephosphorylation caused by decreased Cx43 expression, resulting in the occurrence of exercise-induced myocardial injury.