| Objective To study the protective effect of astragalus saponin extract(AS)on kidney in diabetic rats and to clarify its mechanism,therefore lay the experimental foundation for the further study of the pharmacological effects of AS on diabetic nephropathy.Method The 32 diabetic rats successfully induced by streptozotocin(STZ)were devided into AS high,low dose group,the positive control group(valsartan),model group(DM group),respectively were treated by intragastric administration of AS 200 mg·kgi·d-1,50 mg·kg-1·d-1,valsartan 25 mg·kg-1·d-1,physiological saline 10 ml·kg-1·d-1.8 healthy rats were served as normal control group(NC group,physiological saline 10 ml·kg-1·d-1).All rats were treated for continuous 6 weeks.The body weight was detected every week after treatment,the concentration of blood glucose was monitored on week 2,4 and 6.Total food and waetr intake,total urine in 24h were detected by metabolic cage on week 6,and urine total protein(U-TP),urinary albumin(U-ALB)and urine creatinine(U-CREA)were detected by automatic biochemic-al analyzer,calculate the ratio of U-ALB/U-CREA.The rats were executed in the end of week 6th,blood sample was obtained from the heart by puncture,blood urea nitrogen(BUN),serum creatinine(SCr),uric acid(UA),triglyceride(TG)high-density lipoprotein cholestero,ligh-density lipoprotein cholestero and so on were detected by automatic biochemical analyzer;the content of serum insulin is detected by Enzyme Linked Immunosorbent Assay(ELISA).Kidney hypertrophy index was calculated,the pathological changes of the kidneys by HE staining were observed under light microscope and the ultrastructure changes of kidneys were also observed under electron microscope.Expression of Nephrin and Podocin mRNA in renal tissue were detected by Real Time Polymerase Chain Reaction.Expression of Nerhrin and Podocin protein in renal tissue were detected by immunohistochemical.Results After modeling for 6 weeks,in DM group,blood glucose,metabolic cost in 24h,kidney weight,kidney hypertrophy index,U-TP,U-ALB,the ratio of U-ALB/U-CREA,BUN,Scr,UA,TG,LDL-C were significantly higher than that in NC group(P<0.01,P<0.05),HDL-C,INS,expression of Nephrin and Podocin mRNA in renal tissue and expression of Nerhrin and Podocin protein in renal tissue were significantly lower than that in NC group(P<0.01,P<0.05);the pathological changes of kidneys was significantly serious under light microscope and the ultrastructure changes of kidneys was also significantly serious under electron microscope;After AS intervention for 6 weeks,metabolic cost in 24h,kidney weight,kidney hypertrophy index,U-TP,U-ALB,the ratio of U-ALB/U-CREA,BUN,Scr,UA,TG,LDL-C were significantly lower(P<0.01,P<0.05),expression of Nephrin and Podocin mRNA and protein in renal tissue were significantly higher(P<0.01,P<0.05)in high dose group than that in DM group.And kidney hypertrophy index,U-ALB,the ratio of U-ALB/U-CREA,BUN,UA,TG were also significantly lower(P<0.05),expression of Nephrin and Podocin mRNA and protein in renal tissue were also significantly higher(P<0.01,P<0.05)in low dose group than that in DM group.The blood glucose,INS,HDL-C have no significant change in both high and low dose group.The pathological changes and the ultrastructure changes of kidneys were both improved in both high and low dose group.Conclusion:Astragalus saponin has some protective effect on kidney in diabetic rats,and the dose of 200 mg·kg-1·d-1 has more obvious protective effect than that in 50 mg·kg-1·d-1.The mechanism may be related to increasing the expression of Nerhrin and Podocin protein in renal tissue,and maintaining the stability of structure and function on podocytes. |
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