Abstract: Objective To investigate the effect and mechanisms of all-trans retinoic acid (at-RA) on expression of connective tissue growth factor(CTGF) in rats with renal tubulointerstitial fibrosis. Methods The animal model of unilateral ureteral obstructive(UUO) in rats were used for the study. Forty SD rats were randomly assigned into 5 groups : sham group(group A)、UUO group (group B)、uuo+ benazepril treating group (group C)and two uuo+ atRA treating groups (group D、E).From the day before operation,the rats underuent intragastric administration of benazepril 10mg/(kg·d) in C group, and by at-RA 10mg/(kg·d) in group D and 20mg/(kg·d) in group E and same doses of sodium chloride in group A and B. The obstructed kidneys were sampled on day 14 after surgery. The degree of tubulointerstitial damage was scored by HE and Masson staining. The expression of CTGF, tumor growth factor-β(TGF-β), α-smooth mused actin (α-SMA) and collagen Ⅲ (col Ⅲ) was assessed by immunohistochemistry staining. Results The levels of CTGF, TGF-β1, α-SMA and col Ⅲ in the UUO groups significantly increased compared to those in group A(P＜0.05) and paralled with the degree of tubulointerstitial damage. at-RA and benazepril inhibited the changes. Conclusion Reduction of interstitial CTGF expression may be an important event by which at-RA prevents renal injury caused by UUO.

Key words: Unilateral uretreal obstructive, Interstitial, Fibrosis, Connectwe tissue growth factor(CTGF)