Studies Of Alfalfa Saponins On Cholesterol Metabolism Of Rats

Hyperlipidemia caused atherosclerosis, and then caused coronary heart disease, cerebral apoplexy, myocardial infarction and other diseases. Control the occurrence of hyperlipemia is of great significance to prevent cardiovascular disease. The statins lipid-lowering drugs commonly used today have some places less than satisfactory. Thus, the therapeutic benefits of plant extracts without side effects have been the focus of extensive studies in recent years. Alfalfa saponins have the effects of regulating lipid metabolism and reducing blood lipid and other biological functions. But the studies on its mechanism is less But there has been no report on the effect of Alfalfa saponins on cholesterol metabolism.This paper have studied on the effect of two different high-fat diets on rats and the effect of Alfalfa saponins on body weight, serum index, liver index and the activity and mRNA expressions of cholesterol-metabolizing enzymes in rats.Exp.1: In order to set up stable and suitable animal model of hyperlipidemia in short period of time,two different high-fat diets were compared. Thirty (200±14.27g) SD male rats were randomly divided into three groups, and were fed with basal diet, high-fat dietⅠandⅡfor four weeks. The body weight of rats were determined every weekend. In the third and fourth weekend, levels of serum triglyceride (TG), toral cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C) were determined. The results showed that compared with the control group, the body weight of rats in high fat dietⅠgroup increased significantly (P<0.05),serum TC level of rats in high fat dietⅠgroup increased markedly (P<0.01), HDL-C and LDL-C level increased significantly (P<0.05), which were better than those of rats in high fat dietⅡgroup. These findings suggested that the hyperlipidemia model of SD male rats can be established in four weeks by feeding with high fat dietⅠ.Exp.2: Objective: To investigate the regulation of alfalfa saponins on cholesterol metabolism in rats. Methods: Forty eight healthy male SD rats (200±18.38g) were randomly divided into six groups: normal control A, model control B, Alfalfa saponins prevention group C, Alfalfa saponins treatment group D, Ginsenoside prevention group E and Ginsenoside treatment group F. Excepting the rats in the normal group, the ones in other groups were all made rats’hyperlipidemia model by feeding of high-fat diet, and the experimental period was eight weeks. Alfalfa saponins and ginsenoside were administered respectively to C and E groups from the first week, D and F groups from the fifth week by gavage. The body weight, liver index and serum lipid 1evels of rats were detected. As well as, livers were taken for his topathological examination. The mRNA and protein expressions of ACAT-2, HMG-CoAr, CYP7A1, LDL-R, StAR and SREBP-2 were measured by Real-time PCR and enzyme linked immunosorbent assay (ELISA) methods respectively. Results: (1) Hyperlipidemia rats were significantly decreased body weight, liver index and serum lipid 1evels(P<0.05), and the fatty degeneration and steatosis in liver were ameliorated by alfalfa saponins. (2) Hyperlipidemia rats were remarkably increased the mRNA and protein expressions of CYP7A1, LDL-R, StAR and SREBP-2, decreased ACAT-2. Conculsion: Alfalfa saponins prevent and treat hyperlipidemia by promoting the transcription and expression of CYP7A1, LDL-R, StAR and SREBP-2, and by inhibiting the transcription and expression of ACAT-2.