2周耐力训练对大鼠骨骼肌肌动蛋白和肌球蛋白重链基因表达的影响

Effects of Treadmill Training on the Expression of α-actin and Myosin Heavy Chain Gene in Muscle of Rats

目的:研究2周跑台训练对雄性SD大鼠骨骼肌肌动蛋白(α-actin)和肌球蛋白重链(myosinheavychain,MHC)基因表达的影响。方法:实验以20只雄性SD大鼠为研究对象,将其随机分为对照组和训练组。运动训练组大鼠进行连续2周强度约为75%VO2max(18.5～24米/分钟,坡度为0°,每次运动50分钟,每天2次)的跑台训练,采用半定量反转录聚合酶链式反应(RT-PCR)测定股四头肌深层肌α-actin和MHCmRNA含量。结果:(1)连续2周跑台训练后,股四头肌α-actinmRNA表达增加了22%(P<0.01)。(2)连续2周跑台训练后,股四头肌MHCIIx、MHCIIbmRNA含量分别是安静对照组的109%(P<0.05)和108%(P<0.001),MHCIIb和MHCImRNA变化不明显,结论:(1)短期耐力训练能够提高骨骼肌α-actin基因表达;(2)短期耐力训练后,快型MHC中的两种慢型MHC异形体———MHCIIx、MHCIIa基因表达增加,但未引起快型MHCIIb和慢型MHCI基因表达的变化。

Objective To investigate the changes in α-actin and myosin heavy chain (MHC) isoforms mRNA expression in skeletal muscles after two weeks treadmill training. Methods Twenty adult male SD rats were randomly divided into the sedentary group and the exercise group. The rats of the exercise group carried out continuous treadmill training with～75% of maximal O2 uptake for two weeks (18.5～24m/min, 0° slope, 50min each section twice a day). A quantitative reverse transcription polymerase chain reaction (RT-PCR) method was used to measure the quantities of α-actin and MHC isoforms mRNA of femoral quadriceps. Results (1) The quantities of α-actin mRNA of femoral quadriceps increase 22%(P<0.01). (2)The contents of MHCIIx, MHCIIb mRNA isoform raised 109%(P<0.05) and 108% (P<0.001) respectively, as compared with the comtrol group, and there was no obvious changes in MHCIIb and MHCI mRNA. Conclusions (1) Exercise training could improve the expression level of α-actin gene in muscle. (2) After short-term endurance training, the expression of slow type MHCIIx, MHCIIa isoforms gene increased, whereas the expression of the fast type MHCIIb and slow type MHCI gene remained unchanged.