EFFECTS OF DIETARY CHOLESTEROL ON LIPIDS METABOLISM IN RATS / 营养学报

ABSTRACT

Objective:To investigate the effect of dietary cholesterol on hepatic TG accumulation in rats. Method:Fourteen male Wistar rats were randomly divided into 2 groups and fed 1% cholesterol or cholesterol free AIN76 diets. After 4 w,serum triglyceride(TG) ,total cholesterol(TC) ,high density lipoprotein cholesterol(HDL-C) ,phospholipids(PL) ,glucose and free fatty acid(NEFA) levels were determined. Hepatic lipid concentrations(TG,TC,PL) and the activities and/or mRNA expression of malic enzyme(ME) ,glucose-6-phosphate dehydrogenase(G6PDH) ,fatty acid synthase(FAS) ,phosphatidate phophatase(PAP) ,carnitine palmitoyl transferase(CPT1,2) ,HMG-CoA reductase,acylCoA-cholesterol acyltransferase(ACAT) ,cholesterol 7?-hydroxylase(CYP7A) were also determined. Results:The serum TC and non-HDL-C levels were significantly increased but TG and HDL-C levels were significantly decreased by cholesterol feeding. The concentrations of hepatic TC and TG were 4-20 folds higher in cholesterol group than those in cholesterol free group. The activities of hepatic ME,G6PDH,FAS,PAP and CPT were depressed by cholesterol(40%,70%,50%,15% and 25% respectively) . The mRNA expression of FAS,CPT1,CPT2,and HMG-CoA reductase were down-regulated(35%,30%,50% and 25% respectively) and CYP7? and ACAT were up regulated(6.5 and 1.6 fold) by cholesterol in liver. Conclusion:The dietary cholesterol increases TG accumulation in liver,but dose not stimulates the activity and the gene expressionof hepatic TG synthesis related enzymes.