不同强度游泳训练对大鼠心脏形态和功能的影响

目的:探讨不同强度的游泳运动对大鼠心脏形态和功能的影响。方法:50只Sprague-Dawley(SD)大鼠被随机分为3组:适度游泳组(Moderate swimming group,MS)、高强度游泳组(High-intensity swimming group,HS)和空白对照组(Sedentary control group,SC)。8周的游泳训练结束后,采用超声心动图检测大鼠心脏的形态和功能指标。结果:与SC相比,MS组和HS组大鼠心脏重量分别增加了16%和17%(P<0.01),MS组和HS组大鼠心脏室间隔和左室后壁的厚度显著增加(P<0.001),左室的重量分别增加了36%和41%(P<0.001),但MS组和HS组左室的重量无显著改变。与安静对照组相比,MS组和HS左室内径、每搏输出量、心输出量和射血分数均显著增加。组织多普勒结果显示MS组和HS组大鼠心脏二尖瓣环舒张早期峰值速度(Ea)都有不同程度的增加,而二尖瓣环舒张晚期峰值速度(Aa)几乎没有改变,导致MS组和HS组Ea/Aa显著高于SC组(P<0.01),并且,HS组Ea/Aa显著高于MS组(P<0.01)。结论:(1)长期游泳训练能有效地提高大鼠的心脏功能,其主要生理特征表现为提高安静状态下心脏舒张功能,可导致心肌的能量利用出现节省化;(2)运动训练强度可能比训练时间更能有效提高大鼠心脏舒张功能;(3)大强度的游泳运动并不能导致病理性心肌肥大征象的出现。

Effects of Different-intensity Swimming Training on Cardiac Morphology and Function in Rats

The purpose of this study is to determine the relationship between swimming training and cardiac function in rats. Fifty Sprague-Dawley rats were separated into 3 groups: Moderate swimming group(MS), High-intensity swimming group(HS) and Sedentary control group(SC). After 8 weeks' training, the MS and HS rats' heart weight increased the by 16% and 17%, respectively. Rats were studied by standard and tissue Doppler echocardiography. Echocardiography showed increased septal and posterior wall thickness in MS and HS rats, and increased LV mass by 36% and 41% in MS and HS rats, respectively. LV diameters, stroke volumes, cardiac output, and ejection fractions were unchanged. There was a progressive increase in Ea in MS rats and HS rats, but no significant differences were found in Aa between MS and HS rats, this led to significant progressive increased Ea/Aa in MS rats and HS rats, which was paralleled to training intensity. Conclusion: (1)Chronic intermittent swimming training can improve cardiac function, especially diastolic function in rats; (2)Training intensity is more effective than duration; (3)High-Intensity swimming training can't induce phenomena of pathological cardiac hypertrophy.