Effects of cholesterol overload on visfatin secretion from adipocytes and the mechanism / 中华内分泌代谢杂志

ABSTRACT

3T3-L1 adipocytes were cultured and differentiated into mature adipocytes in vitro. The adipocytes were intervened by ACAT inhibitor( 2 μg/ml) and ox-LDL with various concentrations (0,25,50,75,and 100 μg/ml)for 48 h,ACAT inhibitor( 2 μg/ml) and ox-LDL( 50 μg/ml) at the 0,6,18,36,and 48 h,or ACAT inhibitor( 2 μg/ml),ox-LDL( 50 μg/ml),and TUDCA with various concentrations(0,100,200,and 400 μ mol/L)for 48 h,respectively.The levels of visfatin in supernatant were examined by ELISA and the expressions of protein GRP78 and CHOP in adipocytes were detected by Western blot.After the adipocytes were treated with ACAT inhibitor and ox-LDL at different concentrations for 48 h,the cholesterol concentration and the expressions of GRP78 and CHOP protein in adipocytes and the visfatin levels in the supernatant fluid were increased with the increase of the ox-LDL concentration.The differences had statistical significance in the experimental groups compared with blank control group( all P＜0.05 ).After the intervention with ACAT inhibitor and ox-LDL for different durations,the expressions of GRP78 and CHOP protein in adipocytes and the visfatin levels in the supernatant fluid were up-regulated in a timedependent manner.The differences between experimental groups and blank control had statistical significance( all P＜0.05 ).After the intervention with ACAT inhibitor,ox-LDL,and different concentrations of TUDCA for 48 hours,the expressions of GRP78 and CHOP protein in adipocytes and visfatin levels in the supernatant fluid were down-regulated in a dose-dependent manner and as compared with blank control group the difference were statistically significant( all P＜ 0.05 ).The increase of cholesterol load in adipocyte may promote the visfatin secretion,denoting that the mechanism might be due to the enhancement of endoplasmic reticulum stress in aidpocytes.