Effect of soybean isoflavone on serum lipids, SOD and MDA in ovariectomized rabbits with high cholesterol diet

Objective To study the effects of soybean isoflavone(SI) on serum lipids, superoxide dismutase (SOD) and malondialdehyde (MDA) in ovariectomized rabbits with high cholesterol diet. Methods Thirty-two 6-month-old female New Zealand white rabbits were randomly divided into four groups (n=8 in each group): normal control group (NC), sham-operated and high cholesterol diet group (SO+HC), ovariectomized and high cholesterol diet group (OVX + HC), and ovariectomized,high cholesterol diet and soybean isoflavone group (OVX + HC +SI). The rabbits in NC group were fed normal rabbit diet, and the rabbits in the other three groups were fed 2% high cholesterol diet for 8 weeks. The rabbits in OVX + HC +SI group were also fed soybean isoflavone [500 mg/(kg·d)]. Serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triacylglycerol (TG), superoxide dismutase (SOD) and malondialdehyde (MDA) were measured. Results Serum TC, LDL-C and TG significantly increased in OVX+HC group, and there was significant suppression of SOD activity and obvious increase of serum MDA compared with the other three groups (P0.05). Compared with OVX + HC group serum TC, LDL-C and TG significantly decreased in OVX+HC+SI group, and there was significant increase of SOD activity and obvious decrease of serum MDA (P0.05). Conclusion SI has a protective effect on lipid metabolism and radical damage in the ovariectomized rabbits with high cholesterol diet.