Abstract: BACKGROUND ＆ AIM： To study the effect of soy isoflavones on PPARδ expression in a menopause rat model where the ovaries were removed. MATERIALS AND METHODS： Sixty female SD rats without ovary and weighing 200±20g before the experiment were studied, 10 were fed normal diet as normal control(without soybean),50 were fed high lipid diet containing high cholesterol, high fat and high cholic acid salt for 4 weeks,then divided into 5 group randomly: 3 of these groups were fed high lipid diet with different levels of isoflavone, 30 mg/kg, 90 mg/kg and 270 mg/kg, one group was fed high lipid diet with 0.25 mg/kg estrogen as estrogen control(EC) because of the estrogen effect of isoflavone,and one group was fed high lipid diet all the time only to serve as a atherolsclerosis(AS) model. After 22 week,rats were killed and the pathological changes on the aortic wall and liver were examined and the expression of PPARδ in aortic wall, small intestine and liver were assessed. RESULTS: The aortas and liver of AS model rats were stacked with fat, and the cells were distorted. The groups which were fed high SI or estrogen had less distortion. The expression of PPARδ varied in different groups. CONCLUSION: Supplementation of SI could reduce the formation of arteriosclerosis and protect the aorta and liver of rats fed on high lipid diet from damage. SI also had effects on the expression of PPARδ in rats fed on high lipid diet.

Key words: soy isoflavones, menopause, atherosclerosis, PPARδ