长期中等强度运动对小鼠骨骼肌HIF-Iα mRNA的表达及葡萄糖转运的影响

摘要

目的:观察长期中等强度运动对小鼠骨骼肌血管内皮生长因子-A(VEGF-A)、葡萄糖转运体1(GLUT-1)、葡萄糖转运体4(GLUT-4)mRNA表达的影响,在此基础上进一步观察运动对缺氧诱导因子lα(HIF-1α )mRNA表达的影响,初步探讨运动对小鼠骨骼肌葡萄糖转运的影响及其可能机制.方法:健康雄性昆明小鼠24只随机分为运动组和对照组,运动组小鼠给予12周中等强度跑步训练.末次运动后处死所有小鼠,取双侧腓肠肌,光镜及电镜观察显微及超微结构；实时PCR法测定小鼠骨骼肌VEGF-A、GLUT-1、GLUT-4及HIF-1 α mRNA的表达.结果:①运动组小鼠较对照组体重明显增加(P＜0.05)；②骨骼肌肌细胞数目增加、肌纤维增粗,肌原纤维的直径增加,线粒体数目增加；③运动组小鼠骨骼肌VEGF-A、GLUT-1、GLUT-4及HIF-1 α mRNA表达明显高于对照组(分别增加1.68、1.14、2.31、1.92倍,P分别＜0.05、0.01、0.01、0.01).结论:长期中等强度运动可导致小鼠体重增加、肌纤维增粗、线粒体数目增加,VEGF-A mRNA表达增加；可增加骨骼肌GLUT-1、GLUT-4mRNA的表达,其机制可能与上调骨骼肌HIF-1 α mRNA表达有关.%Objective: To investigate the effect of long-term exercise with moderate intensity on the expressions of glucoserntransporter-1 (GLUT-1) and glucose transporter-4 (GLUT-4) mRNA, as well as of hypoxia inducible factor-1 αrn(HIF-lα) and vascular endothelial growth factor-A (VEGF-A) mRNA in skeletal muscles of mice and explore itsrnpossible mechanisms.rnMethod: Kunming male mice (n=24) were randomly divided into exercise group and control group. The mice inrnexercise group were forced to run with moderate intensity on a treadmill. After 12 weeks of exercise, all micernwere sacrificed immediately and both sides of gastrocnemius were harvested. The middle part of tissue samplesrnwere prepared for H & E staining, and analysed under light microscope and transmission electron microscope. Inrnaddition, part of tissues were used to check gene expression by real-time PCR.rnResult: ① Compared to control group, the body weights of exercise group increased significantly^ < 0.05). ② Thernnumber of muscle cells increased, the size of muscle fibers thickened, the diameter of myofihril and! the amountrnof mitochondria increased significantly. ③The expressions of VEGF-A mRNA, GLUT-1 mRNA, GLUT-4 mRNA, and HIF-1 α mRNA in exercise group were significantly higher (increased by 1.68, 1.14, 2.31 and 1.92-fold separately, P<0.05, 0.01, 0.01, 0.01 separately) than those of control group.rnConclusion: ① Long-term exercise with moderate intensity can cause weight gain, thickening of skeletal muscle fibers, increasing of mitochondria amount and expression of VEGF-A mRNA; ②Long-term exercise with moderate intensity can increase the expressions of GLUT-1 mRNA, GLUT-4 mRNA in skeletal muscles. Induction of HIF-1 α mRNA expression in skeletal muscles by exercise might be one of the possible mechanisms.