不同运动方式对大鼠骨骼肌线粒体融合分裂基因及Mfn2、Drp1蛋白表达的影响

目的:比较长时间低强度耐力运动和大强度间歇性运动对骨骼肌线粒体融合分裂基因与蛋白表达的影响,探讨不同运动方式下线粒体管网发生运动适应的动力学差异。方法:30只大鼠随机分为安静组(Con,n=10)、耐力运动组(ET,n=10)、间歇性运动组(SIT,n=10)。间歇性运动组每天进行9～10次10s极量强度(≥42 m/min)间歇跑台运动,间歇时间30～60 s;耐力运动组每天进行30～60 min低强度(≤16.7 m/min)持续跑台运动;每周训练6天,训练8周。最后一次训练结束后休息24 h,安静状态下取腓肠肌,Real-time PCR检测线粒体融合基因Mfn1、Mfn2、OPA1与分裂基因Drp1、hFis1的mRNA表达;Western blot检测线粒体Mfn2、Drp1蛋白水平。结果:(1)ET组Mfn1 mRNA表达显著高于Con组(P<0.05),SIT组Mfn2 mRNA表达显著低于Con组(P<0.05),SIT组OPA1 mRNA表达显著高于ET组(P<0.05)。SIT组Drp1 mRNA表达显著高于Con组(P<0.05)和ET组(P<0.01),ET组和SIT组hFis1 mRNA表达均无显著变化。(2)SIT组线粒体Mfn2蛋白表达显著高于Con组(P<0.05),Drp1蛋白表达显著低于Con组(P<0.05)。结论:线粒体融合分裂基因以及线粒体Mfn2、Drp1蛋白对长时间低强度耐力运动和大强度间歇性运动有不同的适应机制,这来源于运动方案的差异。大强度间歇性运动可能通过Mfn2、Drp1基因转录与蛋白表达水平影响骨骼肌线粒体的融合与分裂;长时间低强度耐力运动可能通过Mfn1基因转录发挥类似作用。

Different Modes of Exercise Affect the Mitochondrial Fusion/Fission Genes and Mfn2, Drp1 Proteins in Skeletal Muscle of Rats

Objective To investigate the effects of interval sprint training and endurance training on the expressions of genes and proteins related to mitochondrial fusion/fission in skeletal muscle.Methods Thirty rats were distributed into three groups:sedentary(Con,n = 10),interval sprint training(SIT,n = 10) and endurance training(ET,n = 10) groups.Rats in SIT underwent 9-10 repeats of a 10-second "all out" treadmill run(≥42 m/min) with 30-60 s of intervals,6 days per week,for a total of 8 weeks.Rats in ET ran on treadmill 30-60 min continuously at the speed of ≤16.7 m/min per day,6 days per week for a total of 8 weeks.Gastrocnemius was excised 24 h after the last training.Real-time PCR was used to detect the mRNA level of genes related to mitochondrial fusion including Mfn1,Mfn2 and OPA1,and genes related to mitochondrial fission including Drp1 and hFis1.Western blot was used to detect the protein level of Mfn2 and Drp1 in mitochondrial fractions.Results(1)Expression of Mfn1 mRNA in ET increased significantly(P < 0.05)and Mfn2 mRNA in SIT decreased significantly(P < 0.05) comparing to that in Con.Expression of OPA1 mRNA in SITwas significantly higher than in ET(P < 0.01).Expression of Drp1 mRNA in SIT was significantly higher in Con(P < 0.05)and in ET(P < 0.05).The changes in expression of hFis1 mRNA in ET and SIT were not significant(2)Expression of mitochondrial Mfn2 protein in SIT significantly increased(P < 0.05) and Drp1 significantly decreased(P < 0.05)comparing to that in Con.Conclusion Different expressions of genes and proteins related to mitochondrial dynamics following the different modes of exercise were found.