Effect of soybean peptide intake on catabolism of cholesterol in rats

Objective To investigate the effects of dietary soybean protein intake on the concentration of serum lipids in hypercholesterolemic rats and to study the mechanisms of them. Methods Following 28 days of inducing the hypercholesterolemia model successfully,rats were fed a purified diet containing either casein or soybean protein.After the experimental diets had been fed for 56 days,fasting animals were killed. Results Comparing with the rats in casein group,the total cholesterol(TC),triglyceride(TG) and apolipoprotein B(apoB) in soybean protein group were significantly low(P0.05).The concentrations of fecal excretion of bile acids were higher in the rats of soybean protein group(P0.05).Whereas,the changes of high density lipoprotein cholesterol,apolipoprotein AI(apoAI) were not significant in these rats.The levels of 3-hydroxy-3-methylglutaryl coenzyme A(HMG-CoA) reductase mRNA and low density lipoprotein receptor mRNA in soybean protein rats were significantly high. Conclusion Dietary soybean protein intake may lower TC.Further researches are needed for study.