生理性缺血训练对慢性心力衰竭大鼠心功能及心肌重构的影响

关键词：生理性缺血训练  慢性心力衰竭  心功能  心肌重构

Keywords:physiological ischemic training, chronic heart failure, cardiac function, myocardial remodeling

摘要：

      摘要 目的：观察生理性缺血训练（PIT）对慢性心衰大鼠心功能及心肌重构的影响，并探讨其可能作用机制。 方法：将30只健康雄性8周龄SPF级Wistar大鼠，按随机数字表法分为假手术组(SO组)、单纯心衰组（CHF组）和生理性缺血训练组（PIT组）。SO组按心衰模型制作：找到左冠状动脉前降支，用线穿过不结扎；CHF组建立慢性心衰大鼠模型；PIT组在CHF组的基础上进行生理性缺血训练，采用止血带环扎大鼠双下肢，缺血5min，再灌注5min，每天4个循环，每周训练5天，持续8周。训练结束后采用小动物超声系统检测心脏结构与功能，ELISA法检测外周血NT-proBNP含量，Western Blot法检测心肌组织Bcl-2及Bax蛋白表达，Masson染色检测心肌胶原含量。 结果：训练8周后，与SO组相比，CHF组和PIT组的左室射血分数（LVEF）和左室短轴缩短率（LVFS）明显降低，左室收缩末内径（LVESD）和左室舒张末内径（LVEDD）明显升高，NT-proBNP水平升高，Bcl-2蛋白相对表达量显著减少，Bax蛋白相对表达量显著增加（P<0.05）；与SO组相比，CHF组胶原容积分数（CVF）显著增加，而PIT组无明显变化（P?0.05）；与CHF组相比，PIT组的LVEF和LVFS均明显升高，LVESD和LVEDD明显降低，NT-proBNP水平降低，Bcl-2蛋白相对表达量显著增加，Bax蛋白相对表达量显著减少，CVF显著降低（P<0.05）。 结论：8周PIT能逆转慢性心衰大鼠心肌重构，改善心功能，与其促进Bcl-2蛋白表达增加，Bax蛋白表达减少，抑制心肌细胞凋亡和心肌纤维化有关。

Abstract:

      Abstract Objective: To investigate the effect of physiological ischemic training (PIT) on cardiac function and myocardial remodeling in rats with chronic heart failure， and to explore its possible mechanism. Method:Thirty 8-week-old male SPF Wistar rats were randomly divided into sham operation group (SO group)， chronic heart failure group (CHF group) and physiological ischemic training group (PIT group). According to the heart failure model， the SO group exhibited the left anterior descending coronary artery， and passed through the line without ligation. The CHF group established a rat model of chronic heart failure. The PIT group performed physiological ischemic training on the basis of the CHF group. Tourniquet was applied to lower limbs of rats for 5min of ischemia and 5min of reperfusion， 4 cycles a day， 5 days a week for 8 weeks. After training， the structure and function of the heart were detected by small animal ultrasound system. The content of NT-proBNP in peripheral blood was detected by ELISA. The expression of Bcl-2 and Bax protein in myocardial tissue was detected by Western-blot. The myocardial collagen content was detected by Masson staining. Result: After 8 weeks of training， compared with SO group， left ventricular ejection fraction（LVEF）and left ventricular fractional shortening（LVFS）were significantly decreased， left ventricular end-systolic diameter（LVESD）and left ventricular end-diastole diameter（LVEDD） were significantly increased， NT-proBNP level was significantly increased， the relative expression of Bcl-2 protein was significantly decreased and the relative expression of Bax protein was significantly increased in CHF group and PIT group (P<0.05). Compared with SO group， the collagen volume fraction (CVF) significantly increased in CHF group， but there was no significant change in PIT group (P?0.05). Compared with CHF group， the LVEF and LVFS were significantly increased， the LVESD and LVEDD were significantly decreased and the NT-proBNP level was decreased， the relative expression of Bcl-2 protein was significantly increased， the relative expression of Bax protein was significantly decreased， and CVF was significantly decreased in PIT group (P<0.05). Conclusion: Eight weeks PIT can reverse myocardial remodeling in rats with chronic heart failure， which is related to the increase of Bcl-2 protein expression， the decrease of Bax protein expression， and the inhibition of cardiomyocyte apoptosis and myocardial fibrosis.