Objective To explore the impact of medicago polymorpha on weight and blood fat of lipid in alimentary obesity rats and the possible mechanism. Methods SD rats were fed with high fat diet for 9 weeks to establish alimentary obesity models of rats. Fifty successfully modeled rats were randomized into model control group

positive control group

high

middle and low dose medicated group

10 rats in each group. Ten normal and healthy rats were set as blank control group. The high

middle and low dose medicated groups were given medicago polymorpha suspension 2

1

0. 5 g /（ kg·d） respectively by gavage. The positive control group was given orlistat capsules 35 mg /（ kg·d） by gavage. The blank control group and the model control group were given equivoluminal（ 15 ml / kg） distilled water by gavage for 6 weeks. Body weights were measured before and after treatment

and total weight increment was calculated. Levels of serum triglyceride（ TG）

low density lipoprotein cholesterol（ LDL-C）

total cholesterol（ TC）and high density lipoprotein cholesterol（ HDL-C）

as well as the expressions of liver lecithin cholesterol acyl transferase（ LCAT）

cholesterol 7α-hydroxylase（ CYP7A1）

peroxide proliferation activated receptorα（ PPARα） mRNA and proteins were determined. Results Compared with the model control group

body weights and total weight increment after administration in each drug administration group decreased. TC

TG and LDL-C in the high dose medicated group and the positive control group decreased

while HDL-C increased（ P < 0. 05 or P < 0. 01）. After treatment

the difference of the expressions of liver tissue PPARα and CYP7A1 mRNA in each group was not significant（ P > 0. 05）. Compared with the model control group

the expression of PPARα protein in the high dose medicated group increased. While the expressions of PPARα and LCAT proteins in the positive control group decreased（ P <0. 05 or P < 0. 01）. Conclusion medicago polymorpha might have effect of losing weight and decreasing blood lipid on alimentary obesity rats. The mechanism might relate to activating the expression of PPARα protein.