Abstract:Objective To observe the preventive and therapeutic effects and the mechanisms of Ginkgo biloba extract(GBE),Captopril,and Valsartan on the early stage of diabetic nephropathy(DN)rats,and to compare the differences among them so as to establish the combination of medication.Methods Dia- betes mellitus models of SD rats were induced by ip STZ and the developed DN rats were divided randomly into four groups:DN rats with 1% carboxymethyl cellulose(CMC)solution treated.(DN group);DN rats with 100 mg/kg of GBE treated(GBE group),DN rats with 10 mg/kg of Captopril treated(CAP group), and DN rats with 15 mg/kg of Valsartan(VAL group).Rats of normal group(NS group)and DN group were treated with 1% CMC solution.After 12-week treatment,samples were collected.The uhrastruc- tural morphology and thickness of glomcrular base membrane(GBM)were observed under transmission electron microscope;CollagenⅣand laminin in kidney cortex were detected by redioimmunity;MMP2 and TIMP2 proteins and CTGF were measured by immunohistochemistry;the expression of TGF-β1 mRNA in kidney cortex were determined by a reverse transcription polymerase chain reaction(RT-PCR).Results GBE,Captopril,and Valsartan could markedly reduce the thickness of GBM,decrease the contents of laminin and collagenⅣof DN rats significantly.They could inhibit the expression of TGF-β1 and CTGF which induced extraeellular matrix(ECM)directly;On the other hand,they could ameliorate the disequi- librium of MMP2 and TIMP2.Furthermore,The effects of GBE on reducing the thickness of GBM were weaker than that of Captopril and Valsartan,and on suppressing the ECM of kidney cortex were stronger than that of the two drugs.Conclusion GBE,Captopril,and Valsartan could all inhibit the accumulation of ECM.Moreover,GBE has the weaker effects on decreasing the thickness of GBM than Captopril and Valsartan,and has the stronger effects on suppressing the ECM of kidney cortex than the two drugs, which means vitally to postpone kidney fibrosis of DN rats on the combination of medication.