有氧运动和衰老对小鼠心肌线粒体DNA缺失及其功能的影响

Effects of Aerobics and Aging on Myocardial Mitochondrial DNA Deletion and Mitochondrial Function in Mice

目的 :观察和探讨有氧运动和衰老对心肌线粒体DNA(mtDNA)缺失和功能的影响。方法 :用聚合酶链反应技术检测了mtDNA的缺失 ,用分光光度法检测了Mn -SOD、GSH -Px、脂褐素和复合物Ⅰ ,用极谱法检测了复合物Ⅳ。结果 :2 0月龄小鼠心肌mtDNA3 866bp缺失较 5月龄小鼠高 ,复合物I活性随增龄而下降 ,但抗氧化酶活性却显著高于年轻鼠 ,脂褐素含量增加。有氧运动训练的小鼠mtDNA3 866bp缺失率明显低于同龄不运动鼠 ,而复合物Ⅰ活性高 ,抗氧化酶无显著性差异。结论 :有氧运动减轻了mtDNA缺失率可能不完全是通过调节自由基代谢而发生效应的 。

Objective To investigate the effects of aerobics and aging on myocardial mitochondrial DNA(mtDNA)deletion and mitochondrial function in mice. Methods To examine the fragment deletion of mtDNA by using polymerase chain reaction technique and electrophoresis, to measure Mn-SOD?GSH-Px?lipofuscin and complex Ⅰ by using spectrophotometry, complex Ⅳ by using polarography. Results The deletion rate of mtDNA was increased in 20-month old mice than in 5-month old mice, the age-associated activity of complex Ⅰ was decreased, activity of antioxidant enzyme and the content of lipofuscin were increased. The deletion rate of mtDNA in trained mice was decreased, complex Ⅰ activity was higher in trained mice than control mice ,antioxidant enzyme activity had no significant change. Conclusion The deletion rate of mtDNA could be decreased by aerobics.It is not all mechanism of free radical metabolism.