Exercise Training On Rat Skeletal Muscle Contractile Protein And Muscle Myosin Heavy Chain ( Mhc ) Isoforms Of Gene Expression

Influences of exercise training on the contraction proteins and the gene expression of myosin heavy chain (MHC) isoforms in rat skeletal muscleobjective: To explore the influences of exercise training on the contraction proteins and the gene expression of myosin heavy chain (MHC) isoforms in rat skeletal muscle, and to supply some basis for next research about the mechanism .Method: To select 20 clean and healthy male Sprague-Dawley(SD) (purchase from Yangzhou University compared animal center) which were 6 weeks ages and weighted from 135g to 150g, the paper divided them into 2 groups stochastically: A,Control,n=10,B,Heavy-load training,HT,n=10。Heavy-load training Group carried onthe long-enduring and great-load running exercise for 8 weeks. The rats of quiet control group took no exercises. The 10 rats of the movement were trained according to the project of rats movement model which was established by Zheng Lu.Each time the rats excercised as a speed from 15 m / min up to 40 m / min increased by 5 m / min every five minutes. Then this speed were maintained until the rats exhausted. After the heavy-load training group finished its last exercises training, in the next morning the rats of this group and the control group were given a general anesthesia with pentobarbital injection into the abdominal cavity or intravenous vein, then were killed . The quadriceps samples were selected and preserved in liquid nitrogen quickly. SDS-PAGE was adapt as follow: Stacking gel was kept under the density of 5%, and separating gel under the density of 10%. Electrophoresis voltage was 160 V for200 minutes. The mRNA gene expression of the four MHC isoforms of the skeletal muscle were measured by Realtime PCR: MHCI, IIa, IIx and IIb. PCR reacting conditions: pre-degeneration: 94℃, 10min. Degeneration: 94℃, 45s, annealing: 55℃, 45s, extension: 72℃, 1min, 72℃, 10min.Results: After the skeletal muscle contraction protein took the SDS-PAGE, a large number of new strips appeared in the collection of illustrative plates in HT group. The range of molecular weight 43 ~ 200 kDa. It supplied some basis for next research at protein level . On the other hand, the gene expression of MHC isoforms measured by Realtime PCR showed: Comparing the two groups , the heavy-load training group was apparently higher than the quiet control group in MHC I mRNA(P <0.05); There was no apparent differences between the two groups in MHC IIx mRNA and MHC IIa mRNA ( P> 0.05);The heavy-load training group was also apparently higher than the quiet control group in MHC IIb mRNA (P <0.01). The changes of the isoforms were not uniform and were selective on this exercise model.Conclusion: On this exercise model, a large number of new protein strips appeared in the collection of illustrative plates in HT group after the skeletal muscle contraction protein took the SDS-PAGE. It is not clear whether they are degraded fragments or new anabolic ones for the next research. On the other hand, the gene expression of MHC isoforms measured by Realtime PCR showed: The heavy-load training group was apparently higher than the quiet control group in MHC I mRNA(P <0.05) and MHC IIb mRNA (P <0.01), but there were no apparent differences between the two groups in MHC IIx mRNA and MHC IIa mRNA ( P> 0.05). The changes of the isoforms were not uniform and were selective on this exercise model. Above effects supplied some basis for next research about the regulation mechanism of Myogenic Regulation Factors(MRFs).