Abstract: Objective: To investigate the protective effect and regulating mechanism of Benazepril combined with Paecilomyces hepiali Chen on rats with renal interstitial fibrosis. Methods: Rats were randomly divided into three groups： the model group(M group), the Benazepril group(B group) and the combination drugs group(U group). 24hour urinary protein excretion and renal function were determined at 8 weeks． Renal pathology and immunohistochemistry were assayed to measure the expression of fibronectin(FN)， collagenⅣ(ColⅣ)， and the transformor growth factorβ1(TGF-β1)． RT-PCR was used to examine the TGF-β1 mRNA, plasminogen activator inhibitor-1(PAI-1)mRNA, and tissue inhibitors of metalloproteinase-1(TIMP-1)mRNA. Results: Combination drugs and Benazepril effectively reduced the levels of 24hour urinary protein excretion, Bun, Scr, TG and Cho（P＜0.01）, but the levels of TP and ALB were significantly increased（P＜0.01）compared with the M group. Furthermore, the levels of BUN, Scr, TG and Cho were also significantly reduced in the U group compared with the B group（P＜0.05）. The levels of 24hour urinary protein excretion, Bun, Scr, TG and Cho were significantly decreased（P＜0.01） and the expression of LN, FN, ColⅣ, TGF-β1, TIMP-1 and PAI-1 was decreased by the combination drugs. Conclusions: Paecilomyces hepiali Chen combined with Benazepril can effectively delay the development of renal interstitial fibrosis.

Key words: Adriamycin nephropathy, Renal interstitial fibrosis, Paecilomyces hepiali Chen