抗阻训练对增龄大鼠骨骼肌线粒体功能的影响

Effects of resistance training on mitochondrial function in skeletal muscle of aging rats

目的:从线粒体动力学的角度,探讨抗阻运动对增龄大鼠骨骼肌线粒体功能的影响。方法:40只雄性SD大鼠随机分为4组:2月龄安静对照组(C1组)、2月龄抗阻运动训练组(R1组)、6月龄安静对照组(C2组)、6月龄抗阻运动训练组(R2组),每组10只。C1、C2组正常喂养,R1、R2组大鼠进行跑台坡度为35°,速度为15 m/min的抗阻运动,一次跑动15 s,间歇30 s,4次为一组,组间间歇3 min,3组为一次循环,一天为2个循环,循环间歇10 min,每周6 d,共8周。采用Western blot法测定各组大鼠股四头肌线粒体融合蛋白2(Mfn2)、GTP酶1(DRP1)蛋白含量,使用流式细胞仪测定各组大鼠股四头肌线粒体膜电位(ΔΨm)、活性氧(ROS)和游离钙(Ca2+)水平。结果:①与C1组相比,R1组大鼠DRP1蛋白升高(P<0.01)、Mfn2蛋白无显著变化,C2组大鼠DRP1、Mfn2蛋白均降低(P均<0.01);与C2组相比,R2组大鼠DRP1、Mfn2蛋白均升高(P<0.01,P<0.05);与R1组相比,R2组DRP1、Mfn2蛋白均降低(P<0.01,P<0.05)。②与C1组相比,R1组Ca2+含量降低(P<0.01)、C2组Ca2+含量升高(P<0.01);与C2组相比,R2组Ca2+含量降低(P<0.01);与R1组相比,R2组Ca2+含量升高(P<0.01)。③与C1组相比,R1组ROS含量有所上升,但无显著性差异,C2组ROS含量升高(P<0.01);与C2组相比,R2组ROS含量降低(P<0.01);与R1组相比,R2组ROS含量升高(P<0.01)。④与C1组相比,C2组ΔΨm降低(P<0.01);与C2组相比,R2组ΔΨm升高(P<0.01);与R1组相比,R2组ΔΨm有所降低,但无统计学差异。结论:大鼠增龄过程中股四头肌线粒体出现Ca2+堆积、活性氧增多、线粒体膜电位下降、融合蛋白减少等现象,抗阻训练可有效改善这些变化。

Objective:To investigate the effects of resistance exercise on mitochondrial function in skeletal muscle of aging rats.Methods:Forty male Sprague-Dawley rats were randomly assigned to 4 groups,2-month sedentary control group(C1;n=10),2-month with resistance training group(R1;n=10),6-month sedentary control group(C2;n=10),6-month with resistance training group(R2;n=10).Rats in R1 and R2 groups were arranged for resistance training for 8 weeks.This program consisted of interval running on a treadmill,speed 15 m·min-1,35°incline,duration 15 s,interval 30 s,4 times/group,3 groups/cycle,2 cycles per day,6 days per week,a total of 8 weeks.The expressions of mitochondrial fusion protein 2(Mfn2)and dynamin-related protein 1(DRP1)in rat quadriceps were detected by Western blot,and the changes of mitochondrial membrane potential(ΔΨm),reactive oxygen species(ROS)and Ca2+concentration were measured by flow cytometry.Results:①Compared with C1 group,the expression of DRP1 protein in R1 group was increased(P<0.01),and the Mfn2 protein in R1 group had no significant difference,both DRP1 and Mfn2 protein in C2 group were decreased(P<0.01);compared with C2 group,the DRP1 and Mfn2 protein in R2 group were similarly increased(P<0.01,P<0.05);compared with R1 group,the DRP1 and Mfn2 protein in R2 group were both decreased(P<0.01).②Compared with C1 group,the Ca2+content of R1 group was decreased(P<0.01)and the Ca2+content of C2 group was increased(P<0.01);Compared with C2 group,the content of Ca2+in R2 group was decreased(P<0.01);compared with R1 group,the Ca2+content in R2 group was increased(P<0.01).③Compared with C1 group,the ROS content in R1 group was increased,but there was no significant difference,while the ROS content in C2 group was increased(P<0.01);compared with C2 group,ROS content in R2 group was decreased(P<0.01);compared with R1 group,the ROS content in R2 group was increased(P<0.01).④Compared with group C1,the levels ofΔΨm in C2 group was decreased(P<0.01);Compared with C2 group,TheΔΨm of R2 group was increased(P<0.01);Compared with group R1,theΔΨm of R2 group was decreased,but there was no statistical difference.Conclusion:During the aging process of rats,mitochondria of quadriceps femoral muscle showed Ca2+accumulation,increased reactive oxygen species,decreased mitochondrial membrane potential,decreased fusion protein and other phenomena,and resistance training could effectively improve these changes.