大负荷运动引起的大鼠心肌收缩力变化及其与心肌自由基、钙离子水平的关系

Study on Heavy Load Training-induced Cardiac Contractility Changes of Rats,and the Relationship between this Changes and the Levels of Cardiac Free Radical,Calcium Ions

目的:获取大负荷跑台运动引起大鼠心肌收缩力动态性变化的信息,总结其变化特征,探讨其变化与心肌自由基、钙离子水平的关系。方法:成年雄性SD大鼠32只,随机分为空白对照组(A组)、运动后即刻组(B组)、运动后3 h组(C组)与运动后24 h组(D组)。运动心力监测仪监测D组大鼠运动前与运动后不同时相的心力信号。测定血清cTnI浓度;测定心肌SOD活性、MDA含量与Ca2+浓度。结果:第一心音幅值在运动后即刻已有下降,随后连续多时相显著低于运动前水平,至运动后24 h时完全恢复。运动引起血清cTnI浓度显著升高,引起心肌SOD活性显著下降、MDA含量显著升高与Ca2+浓度显著升高;上述变化均以C组最明显。结论:大负荷运动引起大鼠心肌收缩力下降,以运动后恢复期最明显,但为可逆性;心肌收缩力下降可能与心肌自由基增多、钙超载有关。

The purpose of this study was to obtain the information about cardiac contractility dynamical changes after once heavy load training on treadmill, summarized its variation characteristics and explored the relationship between this change and the levels of cardiac free radical, calcium ions. 32 grown male SD rats, randomly divides into normal control group （group A）, instantly after exercise group （group B）, and 3h after exercise group （group C）, and 24h after exercise group （group D）. The cardiac contractility signal of group D was used to monitor before exercise and different time after exercise by exercise cardiac contractility monitor. The levels of all groups rats serum cardiac troponin-I （cTnI）, cardiac superoxide dismutase （SOD, malondialdehyde （MDA）and Ca^2＋ were determined. The result showed that first heard sound （S1） amplitude of rats was lower in instantly after exercise, and was further and significant lower in much time follow instantly after exercise, but the amplitude of S1 returned to normal levels at 24 hours after exercise. Exercise caused serum cTnI concentration was significant lower, and caused cardiac SOD activity was significant lower , cardiac MDA quantitative was significant higher and Ca^2＋ concentration was significant higher. These changes were the most obvious of group C. It is concluded that heavy load training may lead rats cardiac contractility to drop, and the most obvious changes occurred convalescence after exercise, but it was reversible. It also hints that there might be some certain relationship between lowing of cardiac contractility and free radical increase, calcium overload.