高脂诱导小鼠肥胖模型中PPAR-γ激动剂对成熟脂肪细胞内JNK信号通路及visfatin分泌的作用研究

PPAR-γ Agonist Mediates JNK Signaling and Visfatin Secretion in High-fat Diet-induced Obese Mice Models

目的探讨PPAR-γ激动剂罗格列酮对高脂诱导的成熟脂肪细胞内JNK信号通路和visfatin分泌的影响及作用机制。方法采用高脂饲料喂养C57BL/6小鼠24周建立体内肥胖模型,并同时给予3 mg·(kg·d)-1罗格列酮干预治疗;采用200μM棕榈酸诱导成熟3T3-L1脂肪细胞12h建立体外肥胖模型,并同时加入1~10μM PPAR-γ激动剂及5μM PPAR-γ抑制剂分别孵育细胞24h。检测细胞或血清中visfatin水平及JNK信号通路中相关分子表达和含量,评价PPAR-γ激动剂对JNK信号通路及visfatin的调节作用。结果在细胞模型中,PPAR-γ激动剂呈剂量依赖性上调PPAR-γ核表达,而下调phospho-JNK表达,同时增加了细胞内visfatin的释放(P<0.05);PPAR-γ抑制剂和PPAR-γ小分子干扰RNA的效应则与PPAR-γ激动剂截然相反(P<0.05或<0.01)。在动物模型中,PPAR-γ激动剂增加了高脂诱导小鼠脂肪组织中PPAR-γ及visfatin的mRNA水平(P<0.05),且visfatin与PPAR-γmRNA水平呈正相关(r2=0.92,P<0.01)。与此同时,PPAR-γ激动剂降低了JNK通路相关炎性分子TNF-1α、MCP-1及IL-6的表达及含量(P<0.05或<0.01)。结论 PPAR-γ激动剂有潜在的抗炎和调节visfatin分泌的作用。

Objective To investigate the effects and mechanisms of peroxisome proliferator-activated receptorγ（PPAR-γ）agonist on c-Jun NH2-terminal kinase（JNK）signaling pathway and visfatin secretion using in high-fat-induced adipocytes.MethodsC57BL/6 mice were fed with high-fat-diet for 24 weeks,and treated by 3 mg＆#183;（kg＆#183;d）-1 rosiglitazone. Mature 3T3-L1 adipocytes were iduceded with 200μM palmitate acid for 12h, and incubated by 1-10μM PPAR-γagonist and 5μM PPAR-γantagonist for 24h,respectively. To evaluate whether PPAR-γagonist regulates the effects of JNK signaling pathway and visfatin,we checked cellular and serum visfatin levels,and examined proteins expression involved in JNK pathway via in vivo and in vitro obesity models.ResultsPPAR-γagonist dose-dependently significantly up-regulated nuclear PPAR-γexpression and down-regulated phospho-JNK expression in vitro,as well as increased cellular visfatin secretion（P〈0.05）. However,PPAR-γantagonist and PPAR-γsiRNA significantly blocked nuclear PPAR-γexpression and elevated phospho-JNK expression（P〈0.05 or 〈0.01）. PPAR-γagonist significantly increased PPAR-γand visfatin mRNA in the white fat tissue of high-fat-induced obese mice（P〈0.05）. Interestingly,the data showed that there was a positive association with visfatin and PPAR-γmRNA level（r2=0.92,P〈0.01）. In addition, PPAR-γagonist significantly lowered TNF-1α,MCP-1,IL-6 expressions and levels involved in JNK pathway in vivo（P〈0.05 or 〈0.01）.ConclusionPPAR-γagonist has potential therapeutic effects on anti-inflammatory and modulation of visfatin secretion.