Objective:To investigate the effects of interleukin-1β（IL-1β）on 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase（HMGCo AR）and lipid accumulation in HepG2 cells. Methods:Low density lipoprotein 200 μg/m L loaded HepG2 cells were treated with 0 ng/m L（control）or 20 ng/m L IL-1β for 24 hours. The mRNA and protein levels of HMGCo AR were measured by real-time PCR（RT-PCR）and Western blot respectively. HMGCo AR activity was evaluated by thin layer chromatography. Cholesterol synthesis was measured by isotopic labeling method. Intracellular lipids were visualized by oil red O staining and quantitatively analyzed by enzymatic method. Results:IL-1β increased the mRNA levels of HMGCo AR to（1.54±0.04）folds（t=5.619

P=0.001）and protein levels to（1.92 ±0.12） folds（t =7.745

P =0.002）

as well as its enzymatic activities to（1.73 ±0.25） folds（t =2.476

P =0.048） in HepG2 cells. IL-1β also increased cellular cholesterol synthesis to（1.32±0.11）folds（t=2.316

P=0.036）. Markedly red-dyed lipid droplets were observed in IL-1β-treated HepG2 cells. In IL-1β-treated HepG2 cells

intracellular total cholesterol（22.43±1.62）was increased to 1.51 folds comparing with that of control group（14.90±1.11）（t=3.845

P=0.018）

and cholesterol ester（3.84±0.20）was increased to 2.72 folds comparing with that of control group（1.41±0.05）（t=11.730

P=0.000）. Conclusion:IL-1β upregulates HMGCo AR mRNA and protein levels

as well as its enzymatic activities

contributing to enhanced de novo cholesterol synthesis and lipid accumulation in HepG2 cells.