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Updated: Jun 3, 2026
Urethral Stricture Induction Followed by Buccal Mucosa Graft Urethroplasty in a Rat Model
Published on: April 28, 2023
Rapamycin inhibits formation of urethral stricture in rabbits
Tie Chong1, De-lai Fu, He-cheng Li
1Department of Urology, the Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an 710004, Shaanxi, People's Republic of China.
Abstract:
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 (R(H), 1.0 mg/day), low-dose rapamycin (R(L), 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 R(H), R(L), DMSO, and NS groups was 36.0, 56.5, 69.1, and 82.9, respectively. Comparison of the rapamycin groups (R(H) and R(L)) 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 R(H) or R(L) 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.
Insights
Rapamycin effectively inhibits urethral stricture formation in rabbits by reducing lumen reduction and preventing fibroblast proliferation and collagen expression, offering a potential therapeutic strategy for urethral stricture.
Area of Science:
- Urology
- Pharmacology
- Fibrosis Research
Background:
- Fibrosis is implicated in urethral stricture formation.
- Rapamycin is known to inhibit various fibrotic conditions.
Purpose of the Study:
- To investigate the efficacy of rapamycin in preventing urethral stricture formation in a rabbit model.
Main Methods:
- Urethral stricture models were created in rabbits via electrocoagulation.
- Rabbits were treated with high-dose rapamycin, low-dose rapamycin, DMSO, or normal saline.
- Stricture severity was assessed using retrograde urethrogram, video-urethroscopy, and histopathology.
Main Results:
- Rapamycin treatment significantly reduced lumen reduction compared to control groups.
- Histological analysis showed reduced fibroblast proliferation and collagen expression in rapamycin-treated rabbits.
- High-dose rapamycin resulted in 36.0% lumen reduction, low-dose in 56.5%, DMSO in 69.1%, and saline in 82.9%.
Conclusions:
- Rapamycin effectively inhibits the formation of experimentally induced urethral stricture in rabbits.
- The mechanism likely involves the inhibition of fibroblast proliferation and collagen expression.
- Rapamycin presents a promising therapeutic agent for managing urethral stricture disease.
