RESUMO
AIM:To investigate the role of Rho-associated kinase ( ROCK) inhibitor fasudil in the formation of rabbit urethral stricture after injury and to observe the cell activity , migration and extracellular matrix synthesis in the rabbit urethra fibroblasts.METHODS:The rabbit model of urethral stricture was established by microsurgical techniques .The rabbits were divided into sham operation group , operation group and fasudil (3 mg/kg, 10 mg/kg, 30 mg/kg) groups.The diameter of the stenosis was measured by retrograde urethrography 3 months after surgery .The fibroblasts were isolated from urethral scar, and then incubated with fasudil (12.5 μmol/L, 25 μmol/L, 50 μmol/L) in the presence of transforming growth factor-β1 (TGF-β1, 10 μg/L).The untreated cells were used for control .The cell activity was measured by MTT assay.The cell migration ability was tested by the method of Transwell chambers .The protein expression of ROCK , α-smooth muscle actin (α-SMA) , collagen I and collagen III was determined by Western blot analysis .RESULTS:Fasudil significantly reduced formation of urethral stricture after injury (P<0.05).Cultured rabbit fibroblasts with different con-centrations of fasudil inhibited the cell activity and cell migration ability (P<0.05).The protein expression of ROCK,α-SMA, collagen I and collagen III was also inhibited by treatment with fasudil in a dose -dependent manner ( P<0.05 ) . CONCLUSION:Fasudil inhibits the formation of extracellular matrix and reduces the incidence of urethral stricture after injury by down-regulating TGF-β1-induced Rho/ROCK pathway activation in the rabbit urethra fibroblasts .