有氧训练对衰老小鼠快缩型骨骼肌蛋白质降解的抑制作用研究

目的:探讨规律有氧训练对衰老小鼠骨骼肌蛋白质降解的影响。方法:17月龄雄性C57BL/6小鼠18只据体重随机纳入对照组(C组)与有氧训练组(AE组)。训练组小鼠以自身体重2.5%的负荷进行8周游泳训练,每周训练6天,每天1次,每次45min。末次训练24h后处死全部小鼠,禁食6h。酶联免疫吸附测定血清TNF-α、IL-1β和IL-6含量,荧光法检测类糜蛋白酶与钙蛋白酶活性,对硝基苯磷酸底物法检测酸性磷酸酶活性,免疫印迹法检测泛素蛋白酶体系统关键蛋白Atrogin-1、MuRF-1、Ubquitin及钙蛋白酶系μ-Calpain表达,色谱法检测腓肠白肌内3-MH含量。结果:8周有氧训练可致衰老小鼠腓肠白肌促炎细胞因子含量、类糜蛋白酶与钙蛋白酶活性、3-MH含量以及Atrogin-1、MuRF-1、Ubquitin与μ-Calpain蛋白表达显著下降,且变化具有显著性意义(P=0.000)。但溶酶体酶活性未见组间差异。结论:有氧训练可削弱衰老小鼠快缩型骨骼肌蛋白质降解,可能具有防治衰老性肌肉萎缩发生发展的潜力,其作用机制可能与其削弱炎性细胞因子生成集聚,进而抑制泛素蛋白酶体与钙蛋白酶系统的活性有关。

Inhibitory effect of aerobic exercise training on protein degradation of fast-twitch skeletal muscle in aging mice

Objective: To explore the effect of regularly aerobic exercise training on protein degradation of skeletal muscle in aging mice.Method: Eighteen seventeen-month-old male C57/BL mice were randomly divided into control group and aerobic exercise training group by body weight. Mice in training group received 8 wks moderate swimming training with 2.5% body weight workload, 45 mins per day, 6 days per wk. Twenty-four hours after the final exercise bout(6 h fasting), mice in both groups were sacrificed. The content of TNF-α, IL-1β and IL-6 in serum were measured with commercial ELISA kit. The chymotrypsin-like enzyme and calpain activity was detected by using fluorescence method. The acid phosphatase activity was measured with para-nitrophenyl phosphate method. The expression of Atrogin-1, MuRF-1, Ubiquitin and μ-Calpain was detected with Western blotting.The content of 3-MH in white gastrocnemius muscle was measured by means of chromatography.Result: When compared with mice in control group, 8 wks swimming exercise training decreased the content of pro-inflammatory cytokines in serum, the chymotrypsin-like enzyme and calpain activity, the content of 3-MH and the expression of Atrogin-1, MuRF-1, Ubiquitin and μ-Calpain with statistical significance(P=0.000).While there was no difference of acid phosphatase activity between groups.Conclusion: Aerobic exercise training attenuates the protein degradation in white gastrocnemius of aging mice.The diminished production and accumulation of pro-inflammatory cytokines, and then the secondary inhibition of both ubiquitin-proteasome and calpain activity may contribute to this function. These results suggest that aerobic exercise training may play a potentially potent role in ameliorating aging-related sarcopenia.