Effects of the Rho kinase inhibitor, hydroxyfasudil, on bladder dysfunction and inflammation in rats with HCl‐induced cystitis

Objective To evaluate the effect of the R ho kinase inhibitor, hydroxyfasudil, on bladder function in a rat model of HCl ‐induced chemical cystitis, and to elucidate the possible mechanisms associated with its therapeutic effect. Methods Female S prague– D awley rats with HCl ‐induced cystitis were given hydroxyfasudil (10 mg/kg, i.p.) for 7 days. Treatment efficacy was determined by comparing bladder function and histopathology to sham and untreated control rats. Bladder function was determined by cystometric analysis. Rho kinase activity was determined by quantitative reverse transcription polymerase chain reaction and signal inhibition of downstream R as homolog member A / R ho kinase signaling molecules by western blot and immunohistochemistry. Results Treatment with hydroxyfasudil significantly improved bladder intercontraction intervals. Rats treated with hydroxyfasudil also showed a significant reduction of histopathological features associated with cystitis. Western blot and immunohistochemistry findings showed that hydroxyfasudil inhibited downstream molecules of Rho kinase that ameliorated changes associated with HCl ‐induced chemical cystitis, such as inflammatory cell recruitment and smooth muscle cell proliferation. Conclusion The findings from the present study suggest a promising therapeutic role for hydroxyfasudil in bladder inflammation associated with cystitis.