有氧运动对2型糖尿病大鼠腓肠肌氧化应激及MAPKs信号通路的影响

目的:研究有氧运动对2型糖尿病大鼠胰岛素抵抗、腓肠肌氧化应激以及MAPKs信号通路的影响。方法:健康雄性Wistar大鼠30只,随机分为正常对照组(C组)、糖尿病对照组(DC组)和有氧运动组(DE组),其中C组以普通饲料喂养,DC组和DE组以高脂饲料喂养。4周后,对DC组和DE组大鼠采用单次注射链脲佐菌素(STZ)的方法建立2型糖尿病大鼠模型,继续高脂饲料喂养4周后,DE组大鼠进行无负重游泳训练6周,训练期间C组大鼠继续以普通饲料喂养,DC组和DE组大鼠继续以高脂饲料喂养。6周后,处死所有大鼠,测试空腹血糖(FBG)、空腹胰岛素(FINS)并计算胰岛素抵抗指数(HOMA-IR),测试腓肠肌超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GPX)活性及丙二醛(MDA)水平,RT-PCR法测试腓肠肌p38和JNK mRNA表达,Western-blot法测试腓肠肌ERK1/2和p-ERK1/2表达。结果:和C组相比,DC组大鼠FBG、FINS和HOMA-IR均显著升高,腓肠肌SOD和GPX活性显著降低而MDA水平显著升高,腓肠肌p38、JNK1、JNK2 mRNA相对表达量显著升高,p-ERK1、ERK2和p-ERK2相对表达量显著升高而ERK1相对表达量差异无统计学意义。与DC组相比,DE组大鼠FBG、FINS和HOMA-IR均显著降低,腓肠肌SOD和GPX活性显著升高而MDA水平显著降低,腓肠肌p38和JNK1 mRNA相对表达量显著升高而JNK2 mRNA相对表达量无统计学意义,腓肠肌p-ERK1、ERK2和p-ERK2相对表达量显著升高而ERK1相对表达量无统计学意义。结论:有氧运动可激活糖尿病大鼠腓肠肌MAPKs信号通路系统,增强机体抗氧化酶SOD和GPX活性,改善糖尿病大鼠氧化应激状态,降低其胰岛素抵抗水平。

Aerobic Exercise Reduces the Level of Insulin Resistance in Diabetic Rats

Objective To study the effect of aerobic exercise on the insulin resistance,oxidative stress and MAPKs signaling pathway of gastrocnemius in type 2 diabetic rats.Methods Thirty healthy male Wistar rats were randomly divided into control group(C,normal diet),diabetic control group(DC,high fat diet),and diabetic aerobic exercise group(DE,high fat diet).After 4 weeks,rats in groups DC and DE were injected with streptozotocin(STZ) for developing type 2 diabetes,and continued feeding high-fat diet for another 4 weeks.Rats in group DE underwent swimming without additional load for 6 weeks.All rats were sacrificed after 6 weeks,and the fasting blood glucose(FBG),fasting insulin(FINS),insulin resistance index(HOMA-IR),gastrocnemius superoxide dismutase(SOD) and glutathione peroxidase(GPX) activities,and malondialdehyde(MDA) levels were tested or calculated.Gastrocnemius p38 and JNK mRNA expression were determined by RT-PCR,and gastrocnemius ERK1/2 and p-ERK1/2 expression by Western-blot method.Results Compared with the rats in group C,FBG,FINS,HOMA-IR and MDA levels increased,gastrocnemius SOD and GPX decreased,MDA level significantly increased,mRNA relative expression levels of p38,JNK1,and JNK2 in gastrocnemius significantly increased in rats of group DC.There was no statistical significance in relative expression level of ERK1.Compared with the group DC,FBG,FINS,HOMA-IR and MDA levels decreased,and gastrocnemius SOD and GPX increased,mRNA relative expression level of p38 and JNK1 in gastrocnemius,and relative expression level of p-ERK1,ERK2 and p-ERK2 significantly increased in group DE.There was no statistical significance in the level of ERK1 and JNK2.Conclusion Aerobic exercise could activate the MAPKs signaling pathway,increase the expression of antioxidant enzymes SOD and GPX,improve the oxidative stress status in gastrocnemius,and thus reduce the level of insulin resistance in diabetic rat.