一次大负荷跑台运动后大鼠心肌能量代谢及线粒体形态动力学的变化研究

Effects of an Acute Heavy Load Treadmill Exercise on the Morphology and Dynamics of Myocardial Mitochondria and Myocardial Energy Metabolism in Rats

目的:观察大负荷运动后大鼠心肌能量代谢及线粒体变化。方法:40只大鼠随机分5组:对照组(C组)、运动后即刻(E0组)、运动后30 min组(E30组)、70 min组(E70组)、110 min组(E110组),每组均为8只;分别测左室心肌ATP、AMP含量、线粒体ST3、ST4和Miro1、Mfn2、Drp1蛋白基因。结果:1)E0组心肌组织ATP浓度略有下降,AMP、AMP/ATP升高;E30组ATP浓度达到最低值(P<0.01),AMP、AMP/ATP都达到峰值(P<0.01),E110组基本恢复。2)E0组ST3、ST4、RCR都升高,E30组ST3达到最高值(P<0.01),E110组基本恢复。3)运动后Miro1、Drp-1的基因和蛋白表达均升高,E0组心肌Miro1表达和蛋白表达都升高到峰值(P<0.01),随后下降,E110组基本恢复;E30组心肌Drp-1表达和蛋白表达都升高到峰值(P<0.01),随后下降,E110组与C比较有差异(P<0.05);运动后Mfn-2的基因和蛋白表达均下降,E30组Mfn-2表达和蛋白表达都下降到最低值(P<0.01)。结论:1)一次大负荷运动后ATP含量减少、AMP含量增加,ST3速率加快,RCR增加,随着恢复时程延长心肌能量代谢逐渐改善,运动后110 min基本恢复正常;2)一次大负荷运动后心肌线粒体移动增多,融合受抑制趋于分裂;重要的是与移动相关的Miro1表达增加也许是融合分裂发生的先驱因素,使分裂多于合成,进而通过其再次分布做出早期阶段的适宜应答。

Objective： To observe the changes of myocardial energy metabolism, mitochondria morphology and dynamics after an acute heavy load exercise. Methods： Forty male rats were randomly divided into 5 groups（ n = 8 ） ： the control group （ C ）, the groups immediately after exercise （ E0）, 30 minutes （ E30）, 70 minutes （E70） and 110 minutes（E110） after exercise respectively. The concentrations of ATP, AMP in left ventricular muscles and the protein and gene expressions of ST3, ST4, Mirol, Mfn2, Drpl in mitochondria were measured. Results ： 1 ） The concentration of ATP decreased slightly and AMP, AMP/ATP increased in E0 group. The concentration of ATP was lowest in E30 group （P 〈0.01 ） while the concentrations of AMP, AMP/ATP were the highest （P 〈0.01 ）. They went back to baseline in E110 group. 2） The protein and gene expressions of ST3, ST4, RCR increased in E0 group, the ST3＇s were highest in E30 group （P 〈0.01 ）, and they were recovered in El10 group. （3） The protein and gene expressions of Mirol and Drpl increased after exercise. Miro 1 increased in E0 group （P 〈 0.01 ） , then it decreased to baseline in E110 group. The protein and gene expressions of Drp - 1 increased to the peak and then decreased, there was significantly different between E110 and C groups （P 〈 0.05 ）. The protein and gene expressions of Mfn - 2 decreased, and were lowest in E30 group （ P 〈 0.01 ）. Conclusion ： 1 ） After an acute heavy load exercise, ATP concentration reduced, AMP concentration raised, and ST3 and RCR increased.Myocardial energy metabolism was improved during the recovery process, and went back to baseline 110 minutes after exercise. 2 ） After an acute heavy load exercise, the movement of myocardial mitochondria increased. Mitochondria＇ fusion was inhibited and mitochondria tended to split. The increase of Mirol＇s expression, which was related to mitochondria movement, may be the important factor for mitochondria＇s fusion and split. It can produce more split than fusion, and mitochondria can response in early stage after its new distribution.