Nrf2/HO-1通路在有氧运动干预2型糖尿病大鼠骨骼肌氧化应激中的作用

关键词：有氧运动  2型糖尿病  氧化应激  Nrf2/HO-1通路  骨骼肌

Keywords:aerobic exercise  type 2 diabetes mellitus  oxidative stress  Nrf2/HO-1 pathway  skeletal muscle

摘要：

      摘要 目的：观察有氧运动对2型糖尿病大鼠糖代谢、骨骼肌氧化应激和Nrf2、HO-1蛋白表达的影响，探讨Nrf2/HO-1通路在有氧运动干预2型糖尿病大鼠骨骼肌氧化应激中的作用。 方法：7周高脂高糖膳食联合一次小剂量腹腔注射链脲佐菌素，建立2型糖尿病大鼠模型。将普通饲料喂养大鼠随机分为空白对照组（C，n=8）和有氧运动对照组（CA，n=8）；将造模成功的大鼠随机分为糖尿病组（D，n=8）和糖尿病有氧运动组（DA，n=8）。CA组和DA组大鼠进行20m/min、60min/d、5d/W的无负重跑台有氧运动，共运动8周。8周有氧运动后，检测各组大鼠体重、空腹血糖（fasting blood glucose，FBG）、空腹胰岛素（fasting insulin，FINS）、糖耐量线下面积（area under the curve，AUC），计算胰岛素抵抗指数（homeostasis model assessment-estimated insulin resistance index，HOMA-IRI）；透射电镜观察骨骼肌超微结构改变；比色法检测骨骼肌超氧化物歧化酶（superoxide dismutase，SOD）活性和丙二醛（malondialdehyde， MDA）含量；Western Blot检测骨骼肌Nrf2、HO-1蛋白表达水平。 结果：与C组相比，D组大鼠FBG、AUC、HOMA-IRI和骨骼肌MDA含量均明显增加（P<0.01），骨骼肌Nrf2蛋白表达也显著上升（P<0.05）；体重、FINS和骨骼肌SOD活性均明显降低（P<0.01）；骨骼肌超微结构出现异常，主要表现为线粒体损伤。8周有氧运动干预后，CA组大鼠骨骼肌Nrf2和HO-1蛋白表达水平较C组显著上升（P<0.01或P<0.05）；与D组相比，DA组大鼠体重、FINS、骨骼肌SOD活性、骨骼肌Nrf2和HO-1蛋白表达水平均明显升高（P<0.05或P<0.01），FBG、AUC、HOMA-IRI和骨骼肌MDA含量均明显降低（P<0.05或P<0.01），骨骼肌超微结构基本恢复正常，线粒体结构较为清晰，仅可见少量线粒体轻微肿胀。 结论：有氧运动可以缓解2型糖尿病大鼠糖代谢紊乱，且可能通过激活Nrf2/HO-1通路进而减轻2型糖尿病大鼠骨骼肌氧化应激和超微结构异常。

Abstract:

      Abstract Objective： To observe the effects of aerobic exercise on glucose metabolism， oxidative stress and nuclear factor E2-related factor 2（Nrf2）， heme oxygenase1（HO-1） protein expression in type 2 diabetic rats; to explore the role of Nrf2/HO-1 pathway in aerobic exercise intervention on skeletal muscle oxidative stress in type 2 diabetic rats. Method： Seven weeks of high fat and high sugar diet combined with a small dose of STZ intraperitoneal injection was used to establish the model of type 2 diabetes mellitus rats. The rats were randomly divided into blank control group(C，n=8) and control + aerobic exercise group(CA，n=8). The rats that were successfully induced to type 2 diabetes were divided into diabetes group (D， n=8) and diabetes+aerobic exercise group (DA， n=8). The rats in CA group and DA group were given aerobic exercise on treadmill without load at 20m/min， 60min/d and 5d/W for 8 weeks. After 8 weeks of aerobic exercise，the body weight， the fasting blood glucose(FBG)，the fasting insulin(FINS) and the area under glucose tolerance(AUC) were measured. The insulin resistance index(HOMA-IRI) was also calculated. Transmission electron microscopy was used to observe the changes of skeletal muscle structure. Biochemical method was used to detect the SOD activity and MDA content of skeletal muscle. The expression levels of Nrf2 and HO-1 in skeletal muscle were detected by Western blot. Result： Compared with the C group， the FBG， AUC， HOMA-IRI and MDA content of skeletal muscle in the D group were significantly increased (P<0.01) and the Nrf2 expression level was also significantly increased (P<0.05). However, the body weight， FINS and SOD activity of skeletal muscle were significantly decreased (P<0.01)， the ultrastructure of skeletal muscle was abnormal and showed mitochondrial damage. After 8 weeks of aerobic exercise intervention， the expression of Nrf2 and HO-1 protein in skeletal muscle of the CA group was significantly increased than those of the C group(P<0.05， P<0.01). Compared with the D group， the body weight， Fins， SOD activity， Nrf2 and HO-1 protein expression levels in the DA group were significantly increased (P<0.05， P<0.01)； the FBG， AUC， HOMA-IRI， MDA content were significantly decreased (P<0.05， P<0.01)， and the ultrastructure of skeletal muscle and mitochondria was basically recovered. Occasionally，only a few mitochondria were slightly swollen. Conclusion： Aerobic exercise can relieve glucose metabolism disorder and may alleviate oxidative stress and ultrastructure abnormality of skeletal muscle via activating Nrf2/HO-1 pathway in T2DM rats.