Effects of different frequencies of physical training on electron transport chain and oxidative damage in healthy mice

Abstract Aims: The present study investigated the effect of different frequencies (three and five times a week) on electron transport chain and oxidative stress after 8 weeks of run training. Methods: Eighteen male mice (CF1, 30-35g) were distributed into the following groups (n=6): untrained (UT); trained three-time per week (T3) and trained five- time per week (T5). All training sessions were at the same intensity and duration (45min/day) in a treadmill for small animals. Forty-eight hours after the last training session, the animals were killed by decapitation and quadriceps (red portion) was removed and stored at -70ºC. Succinate dehydrogenase (SDH), complexes I, II, II-III, IV and hydroperoxides were measured. Results: Training sessions for five times per week were more effective in increasing the mitochondrial respiratory chain enzyme activities (SDH, complexes I, II, II-III, IV) as well as in decreasing the formation hydroperoxides than sessions performed for three times training per week (p<0.05). Conclusion: Our findings clearly showed that a higher the frequency of training session promotes a greater activity of the electron transport chain and consequently reduces the oxidative stress in healthy animals.摘要 研究目的：本研究旨在探讨8周跑台训练后，不同训练频率（每周3次与每周5次）对电子传递链（electron transport chain）与氧化应激（oxidative stress）的影响。 实验方法：选取18只体重30~35g的雄性CF1小鼠，随机分为3组（每组n=6）：未训练组（UT）、每周3次训练组（T3）及每周5次训练组（T5）。所有训练均采用小动物跑台完成，运动强度与时长保持一致（每日45分钟）。末次训练后48小时，采用断头法处死小鼠，摘取股四头肌红肌部分，置于-70℃环境中保存待测。检测指标包括琥珀酸脱氢酶（succinate dehydrogenase, SDH）、呼吸链复合物I、II、II-III、IV以及氢过氧化物（hydroperoxides）水平。 实验结果：与每周3次训练相比，每周5次训练可更显著提升线粒体呼吸链酶活性（SDH、复合物I、II、II-III、IV），同时更有效抑制氢过氧化物的生成（p<0.05）。 研究结论：本研究结果明确证实，更高的训练频率可促进健康小鼠体内电子传递链活性提升，进而降低氧化应激水平。