Effects of high-fat diet on fatty acid metabolism in liver and insulin sensitivity in aged rats / 中华老年医学杂志

ABSTRACT

Objective To investigate the effects of high-fat diet on fatty acid metabolism in liver and insulin sensitivity in aged rats and to explore the mechanisms of insulin resistance associated with aging. Methods Male Wistar rats aged 22-24 months were randomly divided into old control (OC) group and high-fat diet (HF) group. Male Wistar rats aged 4-5 months were selected as young control (YC) group. The rats in OC and YC were fed with basic diet, and the rats in HF group received high fat diet. Insulin sensitivity was evaluated by hyperinsulinemic-euglycemic clamp technique. Extracted liver triglyceride was measured by an automated biochemistry analyzer. Results (1) Compared with YC group, fasting blood glucose(FBG), fasting insulin(FINS) and free fatty acid were increased in OC group and were increased significantly in HF group. Triglyceride(TG) and total cholesterol(TC) levels were also elevated in HF group. (2) Compared with YC group, glucose infusion rate (GIR) was reduced in OC group and was decreased significantly in HF group. GIR was lower at the end of the 8th week than that at the end of the 4th week in HF group. (3) Compared with YC group, liver triglyceride was increased in OC group and was increased significantly in HF group. Liver triglyceride was negatively correlated with GIR, and positively correlated with FBG. Conclusions Compared with young rats, abnormal fatty acid metabolism and insulin resistance always exist in aged rats. High-fat feeding results in a significant increase in lipid content in liver and more serious insulin resistance in aged rats. Lipid accumulation in liver may contribute to insulin resistance associated with aging and high-fat diet.