有氧运动联合维生素D干预改善db/db小鼠糖、脂代谢及肝脏炎症与氧化应激紊乱

Aerobic Exercise Combined with Vitamin D Intervention Regulates Glucose and Lipid Metabolism and Improves Liver Inflammation and Oxidative Stress in db/db Mice

目的:探讨有氧运动、维生素D以及有氧运动联合维生素D对db/db小鼠糖、脂代谢的调节效果及可能机制。方法:SPF级db/db雄性小鼠32只,随机分为对照组(CG组)、有氧运动干预组(EG组)、维生素D注射干预组(VG组)和有氧运动联合维生素D注射干预组(EVG组),每组8只。EG和EVG组每周进行5天中等强度递增负荷有氧运动,VG及EVG组腹腔注射1,25(OH)2D3干预,剂量为7μg/(kg·d)、每周3次,共干预8周。实验期间采血测试血糖。实验结束后,采血测试血清胰岛素、血脂四项;摘取肝脏测试肝糖原、C反应蛋白(CRP)、肿瘤坏死因子-α(TNF-α)、白介素-6(IL-6)、丙二醛(MDA)、谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)、核转录因子(NF-κB)、葡萄糖转运体4(Glut)的表达,肝组织切片进行HE染色并观察结果。结果:(1)在干预期间,干预组小鼠空腹血糖从干预第4周开始下降,至第8周时,EG、VG和EVG组均显著低于CG组(P<0.01)。8周干预后,EG、VG和EVG组小鼠血清胰岛素水平显著低于CG组(P<0.05);各干预组肝糖原含量高于CG组,且EG和EVG组糖原含量显著高于CG组(P<0.05)。(2)8周干预后,各干预组小鼠血清甘油三酯(TG)、总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-C)均低于CG组,但VG组TC下降无显著差异;干预组小鼠高密度脂蛋白胆固醇(HDL-C)均高于CG组,且EVG组含量显著高于CG和VG组(P<0.05)。(3)HE染色结果显示,CG组大鼠肝组织出现弥漫性的脂肪变性,肝细胞脂质沉积比较明显,出现较多大小不一的空泡;EG和VG组小鼠有所改善,空泡变性减少,EVG组肝细胞排列整齐,脂质沉积和空胞明显减少。(4)8周干预后,EG、VG和EVG组炎症因子IL-6、TNF-α、CRP表达均显著低于CG组(P<0.05),抗氧化酶SOD、GSH-Px活性均显著高于CG组(P<0.05),且EVG组显著高于VG组,各干预组MDA显著低于CG组(P<0.05)。(5)8周干预后,干预组小鼠的肝脏NF-κB表达均显著低于CG组(P<0.01),Glut4蛋白表达均显著高于CG组(P<0.05)。结论:8周有氧运动、维生素D和有氧运动联合维生素D注射干预可改善db/db小鼠糖、脂代谢紊乱,降低血清胰岛素和空腹血糖水平、改善血清脂质水平,降低肝脏脂质沉积和肝细胞脂肪变性,肝糖原贮量增加;其机制可能与运动或/和维生素D通过提高肝脏抗氧化酶活性、降低肝细胞氧化应激和炎症水平有关。

ObjectiveTo explore the effect of aerobic exercise,vitamin D and aerobic exercise combined with vitamin D on glucose and lipid metabolism in db/db mice,as well as the potential mechanism.MethodsThirty-two specific pathogen free male db/db mice were randomly divided into a control group(CG),an aerobic exercise group(EG),a vitamin D injection group(VG)and an aerobic exercise combined with vitamin D injection group(EVG).EG and EVG preformed moderate-intensity aerobic exercise with increased load 5 days per week,while VG and EVG received intraperitoneal injection of 1,25(OH)2 D3(7μg)/(kg·d)3 times per week for 8 weeks.Blood fasting blood glucose(FBG)was measured during the intervention.At the end of the intervention,blood samples were collected to detect FBG,fasting serum insulin(FSI)and blood lipids.The liver was taken to measure the liver glycogen,C-reactive protein(CRP),tumor necrosis factor-α(TNF-α),interleukin-6(IL-6),malondialdehyde(MDA),glutathione peroxidase(GSH-Px),superoxide dismutase(SOD),nuclear transcription factor(NF-κB)and glucose transporter 4(Glut4).The hematoxylin-eosin(HE)staining was performed on liver tissues.ResultsCompared with the CG,the average FBG of the other 3 groups started to decrease after 3 weeks of intervention and was significantly lower at the end of the intervention.After 8-week intervention,the average FBI of EG,VG and EVG was significantly lower than CG,and the average liver glycogen of the former was higher than CG,with that of EG and EVG significantly higher than CG(P<0.05).After the intervention of 8 weeks,the average blood triglyceride(TG),total cholesterol(TC)and low-density lipoprotein cholesterol(LDL-C)of EG,VG and EVG was lower than CG,but the decrease in TC of VG was not significant.A significant increase was observed in the high-density lipoprotein cholesterol(HDL-C)in EVG compared with CG and VG,with the average HDL-C of EG,VG and EVG higher than CG.The HE staining showed that liver tissues of CG were characterized by diffuse hepatic steatosis,obvious triglyceride accumulation and many vacuoles of different sizes,with the decreased number of vacuoles in EG and VG,and obvious decrease in the triglyceride accumulation and number of vacuoles,and neatly-arranged hepatocytes in EVG.Compared with CG group,the average expression of inflammatory factors(IL-6,TNF-αand CRP)and MDA in EG,VG and EVG decreased significantly,while the activities of antioxidant enzymes SOD and GSH-Px increased significantly(P<0.05)after 8-week intervention.Moreover,the average NF-κB expression in the liver decreased significantly,while the expression of Glut4 protein increased significantly(P<0.05)after the intervention of 8 weeks(P<0.01,P<0.05).ConclusionEight-week aerobic exercise,vitamin D and aerobic exercise combined with vitamin D injection intervention can decrease the levels of serum insulin,fasting blood glucose,serum lipids,liver lipid deposition and hepatocyte steatosis,and increase liver glycogen storage in db/db mice,which suggests the beneficial effect of exercise or/and vitamin D on the improvement of glucose and lipid metabolism via increasing liver antioxidant enzymes activity and decreasing hepatic oxidative stress and inflammation.