中等强度游泳运动调控PPARγ/NF-κB/ADPN通路对2型糖尿病大鼠肝脏糖脂代谢紊乱的影响

Effects of moderate-intensity swimming exercise on hepatic glucose and lipid metabolism disorder in type 2 diabetic rats by regulating PPAR/NF-kB/ADPN pathway

目的:探讨中等强度游泳运动对2型糖尿病大鼠(type 2 diabetes mellitus,T2DM)肝脏糖脂代谢紊乱的影响及可能机制。方法:8周龄雄性SD大鼠,随机数字表法抽取8只作为空白对照组(NC组),普食喂养,其余高脂高糖适应性喂养1周后,腹腔注射链脲佐菌素(30mg/kg)制备T2DM大鼠模型。随机选取16只为2型糖尿病模型组(DC组)、2型糖尿病有氧运动组(DS组),每组8只。有氧运动采取无负重游泳干预,以15min/d的运动时间适应性训练3天后,每周逐渐递增直至60min/d,5天/周,共训练8周。实验期间检测各组大鼠体重、血糖、肝脏指数;ELISA法检测血清胰岛素(insulin)、肿瘤坏死因子-α(TNF-α)、白介素-6(IL-6)、白介素-1β(IL-1β)、血清总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)及血清丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转移酶(AST)的含量;检测肝脏组织过氧化物酶体增殖物激活受体γ(PPARγ)、细胞核因子-κB(NF-κB)、脂联素(ADPN)的表达变化。结果:8周有氧运动干预后,与DC组相比,DS组大鼠体重显著上升,血糖显著下降(P<0.01),血清insulin和HDL-C水平均显著上升(P<0.01),血清TNF-α、IL-6、IL-1β和TC、TG、LDL-C、ALT、AST含量均显著下降(P<0.05或P<0.01),肝指数、油红O染色阳性面积显著下降(P<0.01),肝糖原染色阳性面积显著上升(P<0.01),肝组织细胞排列整齐,脂肪空泡、脂滴及炎性细胞浸润显著改善,肝脏PPARγ、GLUT4、ADPN的蛋白和m RNA表达水平显著上升(P<0.05或P<0.01),PPARγ、ADPN免疫荧光阳性细胞水平显著增多(P<0.01),NF-κB的m RNA和免疫荧光阳性细胞水平显著降低(P<0.05或P<0.01),ADIPOR2的m RNA水平显著升高(P<0.05),NF-κB、IL-6的蛋白表达水平显著下降(P<0.01)。结论:8周中等强度游泳运动可通过调控T2DM大鼠肝脏的炎症反应,改善糖脂代谢紊乱,其机制可能与PPARγ/NF-κB/ADPN通路有关。

Objeetive:To explore the ffect of moderate-intensity swimming exercise on liver glucose and lipid metabolism disorder in type 2 diabetic rats and possible mechanism.Method:Eight-weck-old male SD rats were randomly selected as a blank control group(negative control group,NC group)and fed with normal food,while the rest were fed with high-fat and high-sugar adaptively for one week.Streptozotocin(Streptozotocin,STZ,30mg/kg)was injected intraperitoneally to produce the T2DM rat model.Sixteen rats were randomly selected as type 2 diabetes model group(diabetic model group,DC group)and type 2 diabetes aerobic exercise group(diabetic swimming group,DS group),with eight rats in each group.Aerobic exercise was intervened by non-weight-bearing swimming.After 3 days of adaptive training,the exercise time was 15min/day,and gradually increased to 60min/day,5 days/week,for a total of 8 weeks of training.During the experiment,the body weight,blood sugar,and liver index of rats in each group were detected;ELISA was used to detect the serum insulin(insulin),tumor necrosis factor-α(TNF-α),interleukin-6(IL-6),interleukin-1β(IL-1β),serum total cholesterol(TC),triglyceride(TG),low-density lipoprotein cholesterol(LDL-C),HDL Lipoprotein cholesterol(HDL-C)and serum alanine aminotransferase(ALT)and aspartate aminotransferase(AST)levels;the expression changes of peroxisome proliferator-activated receptor(PPAR),nuclear factor-kB(NF-kB)and adiponectin(ADPN)in liver tissue were detected.Result:After 8 weeks of aerobic exercise intervention,compared with the DC group,the rats in the DS group had significantly increased body weight,significantly decreased blood sugar(P<0.01),and significantly increased serum insulin and HDL-C levels(P<0.01).The serum TNF-α,IL-6,IL-1βand TC,TG,LDL-C,ALT,AST levels were significantly decreased(P<0.05 or P<0.01).The liver index and oil red O staining positive area decreased significantly(P<0.01).The positive area of liver glycogen staining increased significantly(P<0.01),with neatly arranged liver tissue cells and alleviated fat vacuoles,lipid droplets and inflammatory cell infiltration.The protein and mRNA expression levels of PPAR,GLUT4 and ADPN in the liver were significantly increased(P<0.05 or P<0.01),and the levels of PPAR and ADPN immunofluorescence positive cells were significantly increased(P<0.01).The levels of mRNA and immunofluorescence positive cells of NFkB were significantly decreased(P<0.05 or P<0.01).The mRNA level of ADIPOR2 was also significantly increased(P<0.05),and the protein levels of NF-kB and IL-6 were significantly decreased(P<0.01).Conclusion:8-week moderate-intensity swimming exercise can improve the disturbance of glucose and lipid metabolism by regulating the inflammatory response in the liver of T2DM rats,and the mechanism may be related to the PPARy/NF-B/ADPN pathway.