C反应蛋白对3T3-L1脂肪细胞脂联素表达和分泌的影响

目的 观察C反应蛋白(CRP)对313-L1脂肪细胞脂联素的表达和分泌的影响,并探讨其致胰岛素抵抗的作用机制.方法 分别用Northem印迹、Western印迹等方法观察CRP对脂联素表达及分泌的影响.结果 (1)Northern印迹显示25和50μg/ml CRP作用24 h分别使脂联素mRNA表达下降约31%和52%(均P<0.01),呈剂量依赖趋势;50 μg/ml CRP干预12和24 h分别使脂联素的表达下降约42%和52%(均P<0.01),呈时间依赖趋势.(2)Western印迹显示25和50μg/ml CRP作用24 h分别使脂联素的分泌下降约19%和41%(均P<0.01),呈剂量依赖趋势;50μs/ml CRP干预12和24 h分别使脂联素的分泌下降约29%和41%(均P<0.01).(3)用10 μmol/L磷脂酰肌醇3激酶(PDK)抑制剂LY294002与50μg/ml CRP干预313-L1细胞24 h,可部分逆转CRP对脂联素mRNA表达的抑制作用,使脂联素的表达恢复到对照组的77%.结论 CRP通过PDK途径抑制脂肪细胞脂联索的表达和分泌,可能是其导致胰岛素抵抗机制之一.

C-reactive protein inhibits adiponectin gene expression and secretion in 3T3-L1 adipocytes

Objective To investigate the effect of C-reactive protein(CRP)on the production of adiponeetin in 3T3-L1 adipocytes and to explore the possible mechanism of CRP-regulated insulin sensitivity.Methods Northern blot and Western blot were performed to examine the effect of CRP on adiponectin gene expression and secretion in 3T3-L1 adipecytes.Resuits (1)Northern blot analysis revealed that CRP treatment inhibited adipenectin mRNA expression in a dose.dependent manner with significant(31%)inhibition detectable at 25μg/ml(P<0.01)and a maximal(52%)decrease found at 50μg/ml(P<0.01).Furthermore,adiponectin mRNA expression was suppressed in a time-dependent manner with significant(42%)inhibition detectable at 12h of CRP treatment and a maximal(52%)inhibition observed at 24 h(both P<0.01).(2)Western blot analysis showed that adiponectin secretion was suppressed in a dose-dependent manner with 19%inhibition detectable with CRP concentration at 25μg/ml(P<0.01)and a significant(41%)reduction found at 50μg/ml(P<0.01).CRP treatment inhibited adiponectin secretion also in a time-dependent manner with significant 29%inhibition detectable at 12 h and a maximal(41%)reduction found at 24 h(P<0.01).(3)Adiponeetin mRNA was decreased bv 52%after CRP treatment for 24 h(P<0.01).Inhibition of phosphatidylinositol 3 kinase(P13K)by LY294002 (10 μmol/L)significantly reversed CRP-inhibited adiponectin mRNA expression,which recovered up to 77%of wild-type levels.Conclusions These results collectively suggest that CRP suppresses adiponeetin gene expression partially through the P13K pathway.which seems to be a mechanism underlying CRP-induced insulin resistance.