Abstract: Objective To observe the effects of berberine on inflammatory factors, adipokines and fatty acid metabolism in 3T3-L1 adipocytes, and to investigate the molecular mechanism underlying berberine improving insulin resistance. Methods Inflammatory molecules , adipokines, key enzymes and protein in fatty acid metabolism mRNA in 3T3-L1 cells were determined with quantitative real time polymerase chain reaction(QRT-PCR) after treated with different concentrations of berberine (0μmol/L,5μmol/L,10μmol/L,20μmol/L and 40μmol/L) for 24 hours while treated with 10μmol/L berberine at different durations (0 h,4 h,8 h,24 h,48 h). These inflammatory factors and key enzymes in fatty acid metabolism mainly included interleukin-6 (IL-6) , tumor necrosis factor-α (TNF-α), leptin, adiponectin, visfatin, fatty acid synthase (FAS), acetyl-CoA carboxylase (ACC), adipose triglyceride lipase (ATGL), adipocyte fatty acid binding protein (AFABP). Results In 3T3-L1 adipocytes, expression of IL-6, TNF-α, leptin, FAS, ATGL, AFABP mRNA reduced with dosage at 10~40μmol/L berberine（P<0.05）while visfatin mRNA level was increased（P<0.05）. No significant difference was found in the expression of adiponectin（P>0.05）. IL-6, TNF-α, leptin, AFABP,ATGL,FAS mRNA decreased with time after 10μmol/L berberine intervention (8-48h) when compared with the control group（P<0.05） while visfatin mRNA level was increased（P<0.05）. Adiponectin mRNA was found to decreased only after treated for 48 h（P<0.05）. No significant difference was found in the expression of ACC mRNA between groups treated with berberine（P>0.05）. Conclusion Berberine has dose and time dependent effects on mRNA expression of inflammatory factors, adipokines, key enzymes and protein in fatty acid metabolism in 3T3-L1 adipocytes, suggesting the mechanisms underlying berberine improving insulin resistance.

Key words: Berberine, 3T3-L1 adipocytes, Insulin resistance, Inflammatory factors, Adipokines, Fatty acid metabolism, Gene expression