不同运动强度下糖尿病大鼠骨骼肌胰岛素受体mRNA表达及氧化应激变化

Expression of insulin receptor mRNA in skeletal muscle and oxidative stress change in diabetic rats at different intensity training

目的观察不同运动强度下糖尿病大鼠骨骼肌胰岛素受体(insulin receptor,InsR)mRNA表达及氧化应激变化。方法将SD大鼠分为5组:正常对照组(A组)、糖尿病非运动组(B组)、糖尿病小强度运动组(C组)、糖尿病中等强度运动组(D组)和糖尿病大强度运动组(E组),每组6只。采用高糖高脂饮食饲养4周后一次性腹腔注射链脲佐菌素(streptozotocin,STZ)制备糖尿病大鼠模型。6周跑台运动(小强度、中等强度、大强度运动的跑台速度分别为10、20、35m/min)前后检测空腹血糖(FBG)、空腹血清胰岛素(FINS)、胰岛素抵抗指数(HOMA-IR)、超氧化物歧化酶(SOD)活性、谷胱甘肽过氧化物酶(GSH-Px)活性及丙二醛(MDA)含量,通过逆转录-聚合酶链反应测定InsR mRNA表达水平。结果小强度、中强度、大强度运动组InsR mRNA表达水平分别为(0.55±0.05)、(0.53±0.04)、(0.41±0.05),与糖尿病非运动组(0.46±0.08)相比,中、小强度运动组mRNA表达水平均显著增加(P<0.05)。6周运动后,中、小强度运动组SOD活性较运动前明显增加(P<0.01),大强度运动组GSH-Px活性显著升高(P<0.05),中、小强度运动组MDA含量则明显下降(P<0.01)。结论不同运动强度下糖尿病大鼠骨骼肌胰岛素受体基因表达不一致,可能与氧化应激对胰岛素信号转导的抑制作用有关。

Objective To observe the expression of insulin receptor mRNA in skeletal muscle and the change of oxidative stress in diabetic rats at different intensity training.Methods Sprague-Dawley rats were divided into group A（control group）,group B（non-exercise group）,group C（low-intensity exercise group）,group D（moderate-intensity exercise group） and group E（high-intensity exercise group）,6 rats in each group.A diabetic rat model was induced by injecting streptozotocin（STZ）for 4 weeks after high lipid and glucose breeding.Rats were trained for 6 weeks on a treadmill.Serum glucose and insulin,insulin resistance index（HOMA-IR）,activities of SOD and GSH-Px,and MDA were detected before and after training.Expression levels of InsR mRNA in skeletal muscle were measured by RT-PCR.Results The InsR receptor mRNA expression level in three exercise groups at different intensities was 0.55±0.05,0.53±0.04,and 0.41±0.05,respectively,and was significantly higher in low and moderate intensity exercise groups than in group B （P0.05）.Six weeks after training,the activity of SOD was significantly higher in low and moderate intensity exercise groups（P0.01）,the activity of GSH-Px was significantly higher in high-intensity exercise group（P0.05）while the MDA level was lower in low and moderate intensity exercise groups than in group B（P0.01）.Conclusion The InsR receptor mRNA expression is different in skeletal muscle of diabetic rats at different intensity training,which may be related to the inhibitory effect of oxidative stress on insulin signal transduction.