BACKGROUND:Signal transducer and activator of transcription 3 (STAT3) and Caspase-3 are the important factors in JAK2/STAT3 signaling pathway. However, there are few studies on their role in the exercise preconditioning for myocardial protection. OBJECTIVE: To analyze the effects of exercise preconditioning on the expression of STAT3 and Caspase-3 in the heart of rats and investigate the cardioprotective mechanism of action. METHODS: Eighty Sprague-Dawley rats were randomly divided into control, exhaustive, exercise preconditioning, and exercise preconditioning+AG490 groups. The exercise preconditioning rat models were established by subjecting to intermittent treadmil exercise for 3 successive days. Rats in the control group were fed routinely for 3 days. Rats in the exhaustive group underwent treadmil exercise at 30 m/min until exhaustion after 3 days of routine raise. Rats in the exercise preconditioning group underwent exercise preconditioning for 3 days, and 24 hours later, they underwent treadmil exercises at the speed of 30 m/min until exhaustion. Rats in the exercise %背景：信号转导及转录激活因子3(STAT3)和Caspase-3是JAK2/STAT3信号通路中的重要因子，它们在运动预适应心肌保护中的作用目前相关研究较少。目的：分析运动预适应对大鼠心脏STAT3和Caspase-3表达的影响及其对心脏保护的作用机制。方法：将80只SD大鼠随机分为对照组、力竭组、运动预适应组、运动预适应+AG490组。连续3 d的间歇跑台运动建立运动预适应动物模型。对照组：常规饲养3 d；力竭组：常规饲养3 d后，以30 m/min的速度运动至力竭；运动预适应组：先进行3 d的运动预适应，24 h后以30 m/min的速度运动至力竭；运动预适应+AG490组：在每天运动预适应前10 min，腹腔注射JAK2抑制剂AG490(3 mg/kg)，余处理同运动预适应组。用HBFP染色法检测心肌缺血缺氧改变，用Western blot方法检测心脏STAT3表达，用免疫组织化学方法检测心脏Caspase-3表达。结果与结论：与对照组相比，力竭组心肌缺血缺氧面积、心脏STAT3表达和心脏Caspase-3表达均显著升高；与力竭组相比，运动预适应组心肌缺血缺氧面积和心脏Caspase-3表达均明显降低，而心脏STAT3表达显著升高；与运动预适应组相比，运动预适应+ AG490组心肌缺血缺氧面积和心脏对照组Caspase-3表达均显著升高，而心脏STAT3表达明显降低。提示运动预适应可以通过激活 JAK2/STAT3信号通路，诱导心脏STAT3表达增加，下调心脏Caspase-3表达，减少心肌细胞凋亡，减轻心肌缺血损伤，从而对心肌发挥保护作用。
展开▼
