title: Rapamycin attenuates unilateral ureteral obstruction-induced renal fibrosis.
abstract: Unilateral ureteral obstruction (UUO) is a well-characterized hydronephrosis model exhibiting interstitial inflammatory-cell infiltration and tubular dilatation followed by tubulointerstitial fibrosis of the obstructed kidney. Our recent report indicates that rapamycin is effective for 50% of transplant recipients with chronic allograft nephropathy. In this study, we investigate the effect of rapamycin on UUO-induced renal fibrosis. UUO or sham-operated rats were randomly assigned to rapamycin or vehicle and were killed on days 7 and 14 after UUO or sham operation. Rapamycin decreased cross-sectional and gross-morphology changes in the obstructed kidney significantly. Rapamycin markedly blunted the increase in weight of the obstructed kidney, obstructed kidney length, and the obstructed/non-obstructed kidney weight ratio (by 74.6, 42.8, and 61.6% on day 14, respectively, all P<0.01). The scores for tubular dilatation, interstitial volume, interstitial collagen deposition, and alpha-smooth muscle actin (alpha-SMA) after UUO were significantly reduced by rapamycin. Rapamycin also decreased the number of infiltrative anti-ED1-positive cells and the gene expression of transforming growth factor (TGF)-beta1 (84.8 and 80.2% on day 7) after UUO (both P<0.01). By double immunostaining and Western analysis, rapamycin blocked the TGF-beta1-induced loss of E-cadherin expression and de novo increase of the expression of alpha-SMA in a dose-dependent manner. In conclusion, rapamycin significantly attenuated tubulointerstitial damage in a UUO-induced rat model of renal fibrosis, suggesting that rapamycin may have the potential to delay the progression of tubulointerstitial renal fibrosis.
authors.affiliation: Division of Nephrology, Department of Medicine, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: M-J
authors.initials: MJ
authors.lastname: Wu
authors.forename: M-C
authors.initials: MC
authors.lastname: Wen
authors.forename: Y-T
authors.initials: YT
authors.lastname: Chiu
authors.forename: Y-Y
authors.initials: YY
authors.lastname: Chiou
authors.forename: K-H
authors.initials: KH
authors.lastname: Shu
authors.forename: M-J
authors.initials: MJ
authors.lastname: Tang
mesh_terms: D000818:Animals; D005355:Fibrosis / Q000209:etiology / Q000517:prevention & control; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D007668:Kidney / Q000473:pathology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D020123:Sirolimus / Q000627:therapeutic use*; D014517:Ureteral Obstruction / Q000150:complications*
chemical_list: D007166:Immunosuppressive Agents; D020123:Sirolimus