摘要
目的:探讨熊果酸改善自发性2型糖尿病KKAy小鼠肝脏胰岛素抵抗的作用和机制。方法:KKAy小鼠35只,随机分为对照组、罗格列酮组、非诺贝特组、熊果酸高剂量组和熊果酸低剂量组,每组7只,以C57BL/6J小鼠作为正常对照。干预4周后,酶联免疫吸附法检测血清游离脂肪酸(free fatty acid,FFA)、肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)和脂联素含量,蛋白质印迹法检测磷酸烯醇式丙酮酸羧激酶(phosphoenolpyruvate carboxykinase,PEP-CK)、胰岛素受体底物2(insulin receptor substrate-2,IRS-2)及葡萄糖转运因子2(glucose transport factor-2,GLUT-2)的蛋白表达,实时荧光定量聚合酶链式反应法检测PEPCK、IRS-2及GLUT-2mRNA的表达,免疫组织化学法观察肝脏组织中过氧化物酶增殖受体α(peroxisome proliferator-activated receptor α,PPARα)和PPARγ的表达。结果:经药物干预后,与对照组相比,熊果酸高剂量组小鼠血清FFA、TNF-α含量明显降低,脂联素水平明显升高(P<0.01);药物干预4周后,高剂量熊果酸对PEPCK蛋白及其mRNA表达具有明显的抑制作用(P<0.01);低剂量熊果酸能抑制PEPCKmRNA的表达,并可诱导IRS-2磷酸化(P<0.05);高、低剂量熊果酸均可增强KKAy小鼠肝脏中PPARα的表达(P<0.01)。结论:熊果酸可能通过提高肝脏组织PPARα的蛋白表达,调节下游信号转导通路PEPCK转录和诱导IRS-2的磷酸化,影响细胞因子FFA、TNF-α和脂联素的水平,从而改善KKAy小鼠的肝胰岛素抵抗。
OBJECTIVE：To explore the effects and mechanism of ursolic acid in improving hepatic insulin resistance in KKAy mice with spontaneous type 2 diabetes. METHODS：Thirty-five KKAy mice were divided into five groups according to the randomized block design, namely,control,rosiglitazone,fenofibrate,and high-and low-dose ursolic acid groups with seven mice in each group.C57BL/6J mice were used as the normal control group.At the end of the 4th week,free fatty acid（FFA）,tumor necrosis factor-α（TNF-α）and adiponectin contents in serum were detected by enzyme-linked immunosorbent assay;the protein expressions of phosphoenolpyruvate carboxykinase（PEPCK）, insulin receptor substrate-2（IRS-2）and glucose transport factor-2（GLUT-2）were detected by Western blot method;the mRNA expressions of PEPCK,IRS-2 and GLUT-2 were detected by real-time polymerase chain reaction;the expressions of peroxisome proliferator-activated receptorα（PPARα）and peroxisome proliferator-activated receptorγ（PPARγ）in liver tissue were detected by immunohistochemical method. RESULTS：After four weeks of intervention,the contents of FFA,TNF-αand adiponectin in serum of the high-dose ursolic acid group had changed,showing statistically significant difference compared to those of the control group（P0.01）;high dose of ursolic acid had depressant effect on the expressions of PEPCK protein and PEPCK mRNA（P0.01）;low dose of ursolic acid depressed the expression of PEPCK mRNA and induced phosphorylation of IRS-2in the liver（P0.05）;both high and low dose of ursolic acid improved the expression of PPARαin the liver（P0.01）. CONCLUSION：The effects of ursolic acid in improving hepatic insulin resistance in KKAy mice with spontaneous type 2 diabetes may be closely related to affecting the contents of FFA,TNF-αand adiponectin,improving the expression of PPARαprotein,regulating transcription of PEPCK protein and inducing phosphorylation of IRS-2.
出处
《中西医结合学报》
CAS
2012年第7期793-799,共7页
Journal of Chinese Integrative Medicine
基金
国家自然科学基金面上项目(No.81073116)
