Effect of intraurethral Mitomycin-C on healing and fibrosis in rats with experimentally induced urethral stricture

BACKGROUND: In the pathogenesis of urethral stricture, fibrosis is associated with an excessive collagen increase. After the recognition that topical application of Mitomycin-C (MMC) inhibits fibroblast proliferation and is effective in preventing scar formation, many studies have been carried out on this subject outside the scope of urology. The aim of the present study is to observe the intraurethral impact of the employment of low doses of MMC on scar formation and fibrosis in experimental rat model. METHODS: Urethral injuries were made by internal urethrotomy knife. The study was carried out with 35 adult male Wistar albino rats. Five rats were allocated to the control group (group 1), 10 to a group that was administered 2 mg/L MMC (group 2) and 20 to a group that was administered 10 mg/L MMC (group 3). Mitomycin-C was administered to the injured urethra in the form of irrigation for 5 min. The rats were sacrificed 14 days later in order to evaluate chronic inflammation and fibrosis and their penises were histopathologically examined under light microscopy with hematoxilen eosin and trichrom stains. RESULTS: When group 2 was compared with control group, the differences in hemosiderin-laden macrophages (HLM), mononuclear cell infiltration (MCI) and fibrosis were found to be statistically significant (P < 0.01, P < 0.05, P < 0.005, respectively). When group 3 was compared with control group, the differences in HLM, MCI and fibrosis were also found to be statistically significant (P < 0.05, P < 0.05, P < 0.005, respectively). In the comparison of group 2 with group 3, no statistically significant differences were found in terms of the these parameters. CONCLUSIONS: Although MMC is toxic at high doses, the antifibrotic effect of the intraurethral low dose MMC may be useful in combination therapy for internal urethrotomy.