间歇运动激活miR-21-PTEN-Akt通路抑制NLRP3炎症小体表达保护心梗心功能

Aerobic Interval Training Activating miR-21-PTEN-Akt Signaling Pathway,Inhibiting NLRP3 Inflammsome Expression and Improving Myocardial Function in Rats with Myocardial Infarction

目的:探讨间歇运动对心肌梗死(myocardial infarction,MI)大鼠心肌microRNA-21(miR-21)表达和下游PTEN-Akt信号通路与NOD样受体蛋白3(NOD-like receptor protein 3,NLRP3)炎症小体表达的影响。方法:3月龄雄性SD大鼠,左冠状动脉前降支结扎建立MI模型,术后随机分为假手术安静组(C)、假手术+间歇运动组(CE)、心肌梗死安静组(MI)和心梗+间歇运动组(ME),每组10只,其中C和CE组只穿线不结扎。术后1周,CE和ME组大鼠先进行1周适应性运动,再进行4周间歇运动。训练结束后次日,血流动力学检测心功能,获取心肌组织。Masson染色测定心肌胶原容积百分比(collagen volume fraction,CVF%),RT-qPCR检测心肌miR-21表达,Western blot检测心肌NLRP3、ASC、caspase-1、IL-1β、IL-18、PTEN、p-Akt/Akt蛋白表达。结果:与C组比较,CE组大鼠心肌miR-21表达显著升高,PTEN、NLRP3、ASC-1、caspase-1和IL-1β蛋白表达显著降低,p-Akt/Akt比值显著升高,左室舒张末压(left ventricular end-diastolic pressure,LVEDP)显著降低,左室收缩压(left ventricular systolic pressure,LVSP)和±dp/dt max显著升高;MI组大鼠心肌miR-21表达增多,PTEN、NLRP3、ASC-1、caspase-1、IL-1β和IL-18蛋白表达明显增多,p-Akt/Akt比值显著降低,CVF%和LVEDP显著升高,LVSP和±dp/dt max显著降低。与MI组比较,ME组大鼠心肌miR-21表达显著升高,PTEN、NLRP3、ASC-1、caspase-1、IL-1β和IL-18蛋白表达显著降低,p-Akt/Akt比值显著升高,CVF%和LVEDP显著降低,LVSP和±dp/dt max显著升高。心肌NLRP3蛋白表达与LVSP、+dp/dt max、-dp/dt max呈显著负相关,与LVEDP呈显著正相关;心肌miR-21表达与NLRP3蛋白表达呈显著负相关,与LVSP、+dp/dt max、-dp/dt max呈显著正相关,与LVEDP呈显著负相关。结论:间歇运动上调心梗大鼠心肌miR-21表达,激活miR-21-PTEN-Akt信号通路,抑制NLRP3炎症小体表达,抑制心肌炎症反应和重塑。间歇有氧运动改善心梗大鼠心功能与提高心梗大鼠心脏miR-21表达、激活miR-21-PTEN-Akt通路密切关系。

Objective: The present study was to determine the effects of aerobic interval training(AIT) on the expressions of microRNA-21(miR-21), downstream signaling pathway of PTENAkt and NOD-like receptor protein 3(NLRP3) inflammasome in rats with myocardial infarction(MI). Methods: Male Sprague Dawley rats were randomly divided into sham-operated group(C), sham-operated with AIT group(CE), sedentary MI group(MI) and MI with AIT group(ME)(n=10). The MI model was established by ligation the left anterior descending coronary artery. Rats in C and CE groups were subjected to the same surgery, but only threaded and not ligated. One week after surgery, rats in CE and ME groups took adaptability training for 1 week,and then subjected to 4 weeks treadmill exercise training. After training, the level of LVEDP,LVSP and ±dp/dt max were tested in order to evaluate cardiac function. Collagen volume fraction(CVF %) was calculated by Masson Staining. The expression of cardiac miR-21 was examined by RT-qPCR. The protein expression of NLRP3, ASC-1, caspase-1, IL-1β, IL-18, PTEN, pAkt and Akt was examined by western blotting. Results: Compared with the C group, the expressions of cardiac miR-21 and p-Akt/Akt were increased and the protein expression of PTEN,NLRP3, ASC-1, caspase-1 and IL-1β was decreased in the CE group. LVEDP was decreased and LVSP and ±dp/dt max were increased in the CE group. Moreover, compared with the C group, MI significantly increased the expression of miR-21, PTEN, NLRP3, ASC-1, caspase-1,IL-1β and IL-18 and decreased the ratio of p-Akt/Akt, as well as increased LVEDP and CVF%and decreased LVSP and ±dp/dt max in the MI group. Furthermore, compared with the MI group, AIT increased the expressions of cardiac miR-21 and p-Akt/Akt ratio, and decreased the expression of PTEN, NLRP3, ASC-1, caspase-1, IL-1β and IL-18 in the ME group. Meanwhile,LVEDP and CVF% were reduced. LVSP and ±dp/dt max were obviously increased in the ME group. The expression of NLRP3 protein was negatively related to LVSP and ±dp/dt max, and positively related to LVEDP. The expression of miR-21 was negatively related to the expression of NLRP3 protein and LVEDP, and positively related to LVSP and ±dp/dt max. Conclusion:AIT obviously increased the expression of miR-21, and activated miR-21-PTEN-Akt signaling pathway, and inhibited the expression of NLRP3 inflammasome and prevented cardiac inflammatory response. The protective effect of AIT on cardiac function in MI rats was related to the increased expression of miR-21 and the activation of the miR-21-PTEN-Akt signaling pathway.