The Effects Of Rhizoma Dioscoreae Polysaccharides On Hyperglycemia,Hyperlipemia And Oxidative Stress In Type 1 Diabetic Rats

Objective:Rhizoma Dioscoreae is a traditional Chinese medicine,the main efficiency component of which is Rhizoma Dioscoreae polysaccharides(RDP).It was reported that RDP showed antagonistic action on acute liver injury induced by CCl4 in mice,and reduced the blood glucose level in type 1 diabetic rats induced by alloxan in dose-dependent manner.The aim of this study was to study the effects of RDP on hyperglycemia,hyperlipemia and:idative stress in liver and kidney of type 1 diabetic rats induced by STZ.Methods:For the induction of diabetes,a freshly prepared solution of STZ(40 mg/kg w.)in 0.1 M citrate buffer(pH 4.2)was injected to the abdominal cavity of overnight sting male SD rats.The blood glucose level was measured at the 3,7 days after injection.(?)e rats with the blood glucose level over 16.7 mM were considered diabetic and included the further study.Normal and diabetic rats were randomly divided into control group(the me amount of normal saline),low dose group(80 mg/kg)and high dose group(240 mg/kg).tragastric administration of RDP was conducted once daily over a 4 week period.After:atment for 4 weeks,the oral glucose tolerance test(OGTT)was done the day before crifice,then the rats were executed,the levels of fasting blood glucose(FBG),ycosylated hemoglobin(GHb),serum total cholesterol(TC),triglyceride(TG),high density oprotein cholesterol(HLD-C)and low density lipoprotein cholesterol(LDL-C)were tected.Furthermore,the contents of catalase(CAT),superoxide dismutase(SOD),(?)tathione peroxidase(GSH-Px),glutathione(GSH)and malondialdehyde(MDA)in rat livers and kidneys were measured.Results:After oral administration of RDP(240 mg·kg-1·d-1)for continuous 4 weeks,the fasting blood glucose level(FBG)(p<0.05)and lipids(TC,TG and LDL-C)(p<0.05)levels,as well as the content of glycosylated hemoglobin(GHb)(p<0.05)and hepatic MDA(p<0.01)in diabetic rats,were decreased significantly,whereas serum HDL-C level(p<0.05)and renal antioxidant enzymatic GSH-Px activity in diabetic rats,were increased significan-tly.Furthermore,RDP could improve the oral glucose tolerance of diabetes rats induced by STZ(p<0.05).Conclusion:The findings from this study suggest that RDP can alleviate hypergly-cemia,hyperlipemia in STZ induced type 1 diabetic rats,thus inhibiting the deterioration of the condition.RDP also shows good effects on increasing the activities of antioxidative enzymes and inhibiting lipid peroxidation in the liver and kidney of diabetes rats.The results of this paper suggest that the hypoglycemic effects of RDP may be correlated with its antioxidative stress activity in vivo.