Objective To explore the possible role of PGE 1 in tubulointerstitial fibrosis formation. Methods Rat model of unilateral ureteral obstruction(UUO) was established.In situ hybridation(ISH) technique, morphological observation and biochemical analysis were applied to determine TGF? 1 mRNA expression, changes of tubulointerstitium and rencortical hydroxyproline content after used PGE 1. Results 3 days after UUO,the rats renal interstitial edema, a number of mononuclear cells recruitment. On day 14,tubule atrophy, interstitial proliferative fibrosis and area enlarged,hydroxyproline content,TGF? 1 mRNA expression increased, the peak value of the latter occurred early than that of hydroxyproline peak value and interstitial area enlargement.PGE 1 could down -regulate these changes.Conclusions The antagenistic effect of PGE 1 on renal interstitial fibrosis may be partly associated with down-regulating overexpression of TGF? 1 mRNA and inhibiting mononuclear cells recruitment.