Abstract: Objective The aim of this study was to investigate the effect of sirolimus on peripheral blood Treg/Th17 cell ratio in high fat diet-inducednon-alcoholic fatty liver disease (NAFLD) in rats. Methods 60 SD rats were randomly divided into sirolimus intervention group, model group and control group with 20 rats in each group. The NAFLD model was established by high fat diet feeding for 12 weeks and when the model was successfully built up, 20 rats were fed with sirolimus for two weeks.Serum aspartate aminotransferase(AST),alanine aminotransferase (ALT)], blood triglyceride(TG),total cholesterol(TC),high density lipoprotein cholesterol(HDL-C),low density lipoprotein cholesterol(LDL-C)], serum interleukin-10(IL-10), IL-17,tumor necrosis factor-α(TNF-α)] and peripheral blood regulatory T lymphocyte (Treg)/T help cell 17(Th17) were detected. Results At the end of the experiment, serum AST and ALT levels insirolimus-intervened group were (134.9±15.3)U/L and (109.4±18.2)U/L, both significantly lower than 【(151.1±28.9)U/L and (128.9±17.7)U/L, respectively,P<0.05】 in model group; blool TG, TC and LDL-C levels were (0.9±0.3)mmol/L, (2.6±0.8)mmol/L and (3.3±1.2)mmol/L, significantly lower than 【(1.1±0.5)mmol/L, (3.6±1.3)mmol/L and (5.4±1.8)mmol/L, respectively, P＜0.05】 in the model, while blood HDL-C level was (1.3±0.5)mmol/L, much higher than 【(0.7±0.4) mmol/L, P＜0.05】 in the model; serum IL-10 level was (68.9±26.6)pg/ml, much higher than 【(37.8±17.2)pg/ml, P＜0.05], while serum IL-17 and TNF-α levels were (13.2±3.3)pg/ml and (0.7±0.2)ng/ml, significantly lower than 【(22.6±4.0)pg/ml and(1.2±0.4)ng/ml, P＜0.05】 in the model; the percentage of Treg cells was (4.5±0.7)%, the percentage of Th17 cells was (1.7±0.6)% and the ratio of Treg/Th17 cells was (2.6±0.7), significantly different compared to 【(3.8±0.9)%, (2.8±1.1)% and(1.5±0.7), respectively, P＜0.05] in the model.Conclusion The administration of sirolimus could inhibit inflammatory response and correct Treg / Th17 cell imbalance in rats with high fat diet-induced NAFLD, which mightalleviates hepatic steatosis.

Key words: Non-alcoholic fatty liver disease, Sirolimus, High fat diet, Treg / Th17 cells, Rats