PT  - JOURNAL ARTICLE
AU  - Tie Chong
AU  - De-lai Fu
AU  - He-cheng Li
AU  - Hui-bo Zhang
AU  - Peng Zhang
AU  - Wei-min Gan
AU  - Zi-ming Wang
TI  - Rapamycin Inhibits Formation of Urethral Stricture in Rabbits
AID  - 10.1124/jpet.110.178624
DP  - 2011 Jul 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 47--52
VI  - 338
IP  - 1
4099  - http://jpet.aspetjournals.org/content/338/1/47.short
4100  - http://jpet.aspetjournals.org/content/338/1/47.full
SO  - J Pharmacol Exp Ther2011 Jul 01; 338
AB  - Rapamycin has been reported to inhibit hepatic fibrosis, lung fibrosis, renal fibrosis, and subglottic stenosis. Fibrosis is also involved in urethral stricture. Therefore, we investigated the effect of rapamycin on the inhibition of urethral stricture formation in a rabbit model. First, models of urethral stricture were successfully established by electrocoagulation of the bulbar urethra in adult New Zealand male rabbits. Forty-six model rabbits were randomly assigned to four groups: high-dose rapamycin (RH, 1.0 mg/day), low-dose rapamycin (RL, 0.1 mg/day), dimethyl sulfoxide (DMSO) alone (DMSO, solvent control), and normal saline (NS). Urethral stricture was assessed by a retrograde urethrogram and video-urethroscopy. Urethra pathology was evaluated by hematoxylin and eosin and Sirius red staining. After 28 days of treatment, lumen reduction in the RH, RL, DMSO, and NS groups was 36.0, 56.5, 69.1, and 82.9, respectively. Comparison of the rapamycin groups (RH and RL) and control groups (DMSO and NS) indicated significantly less restriction in the rapamycin groups. Histopathological analysis confirmed the presence of fibroblasts and an increase in collagen at the stricture site in the two control groups but not in the RH or RL groups. These results indicate that rapamycin inhibits experimentally induced urethral stricture formation in rabbits. This effect may be due to its inhibition of fibroblast proliferation and collagen expression.