大负荷运动后骨骼肌核心时钟基因Bmal1/Clock、Cry1/Per1的节律性振荡变化趋势

Influence of Heavy Exercise on Rhythmic Oscillation Trend of Skeletal Muscle Core Clock Genes Bmal1/Clock and Cry1/Per1

目的:探讨大负荷运动对骨骼肌核心时钟基因节律性表达的影响。方法:将208只8周龄SD大鼠随机分为对照(control,C)组与运动(Exercise,E)组,E组予以一次大负荷运动训练。每6 h取各组比目鱼肌,采用透射电镜观察骨骼肌纤维超微结构,通过实时荧光定量PCR实验测定骨骼肌核心时钟基因Bmal1、Clock、Cry1、Per1表达量,并使用余弦分析软件circacompare(R package)获取拟合余弦曲线参数,分析其节律性振荡的变化趋势。结果:1)C组Bmal1、Clock、Cry1、Per1 mRNA在72 h内呈现3个完整近日节律周期;E组Bmal1 mRNA、Cry1和Per1mRNA在0~24 h、Clock mRNA在0~72 h近日节律消失。2)与C组相比,E组Bmal1 mRNA在0、6、12和18 h显著升高,Clock mRNA在0 h时显著升高;Cry1、Per1 mRNA在0、12 h显著降低。3)C组各时相肌纤维超微结构正常,E组0、24和48 h均出现不同程度肌小节结构破坏、线粒体肿胀及聚集等改变,72 h有所缓解。结论:一次大负荷运动可诱发骨骼肌核心时钟基因Bmal1/Clock、Cry1/Per1节律振荡紊乱,其变化趋势与肌纤维超微结构损伤时相基本一致。

Objective:To investigate the effect of heavy exercise on the rhythmic oscillation of skeletal muscle core clock genes.Methods:Two hundred and eight 8-week-old SD rats were randomly divided into the control(C)group and the exercise(E)group.The rats in group E were trained with heavy exercise for one time,and the soleus muscles were taken to detect indices every 6 hours.The ultrastructure of skeletal muscle fibers was observed by transmission electron microscope.The expression of skeletal muscle core clock genes,Bmal1,Clock,Cry1 and Per1 were measured by real-time fluorescence quantitative PCR.The parameters of fitting cosine curve were obtained by cosine analysis software circacompare(R package),and the change trend of rhythmic oscillation was analyzed.Results:1)In group C,three complete circadian rhythm cycles were observed of Bmal1,Clock,Cry1 and Per1 mRNA within 72 hours.In group E,the circadian rhythm of Bmal1 mRNA,Cry1 and Per1 mRNA disappeared at 0-24 h,Clock mRNA disappeared at 0-72 h.2)Compared with group C,Bmal1 mRNA in group E increased significantly at 0,6,12 and 18 h,and Clock mRNA increased significantly at 0 h;Cry1,Per1 mRNA decreased significantly at 0 h and 12 h.3)The ultrastructure of muscle fibers in group C was normal at all timepoints.In group E,changes,such as structural destruction of sarcomere,swelling and aggregation of mitochondria,occurred at 0,24 and 48 h,and relieved at 72 h.Conclusions:Heavy exercise could induce the rhythm oscillation disorder of Bmal1/Clock and Cry1/Per1 in skeletal muscle,which tendency was consistent with the ultrastructural damage of skeletal muscle fibers.