Y-27632 improves the erectile dysfunction with ageing in SD rats through adjusting the imbalance between nNo and the Rho-kinase pathways

We investigated whether the effect of Y-27632 to improve the erectile function in SD rats was associated with the degree of the imbalance between nNOS and the Rho-kinase pathways. Western blot analysis was used to evaluate nNOS and Rho-kinase protein expression in 10 young and 10 old SD rats. Imbalance value between nNOS and Rho-kinase protein levels was obtained by subtracting nNOS from Rho-kinase. A 5-V stimulus was given in SD rats before and after the administration of 200 nmol kg(-1) of Y-27632 intracavernosally and ICP/MAP was recorded. The improvement of erectile function induced by Y-27632 was expressed as the margin of ICP/MAP after and before the administration of Y-27632. In young rat group, the contents of nNOS and Rho-kinase protein were 1.7 +/- 0.15 and 1.8 +/- 0.14 respectively. In old rat group, the nNOS protein decreased to 1 +/- 0.15, and in contrast, the Rho-kinase protein increased to 2.6 +/- 0.2. The imbalance value between nNOS and Rho-kinase was 0.2986 +/- 0.1109 and 1.5961 +/- 0.1206 in young and old rat groups. The improvement of erectile function induced by Y-27632 was 0.0500 +/- 0.0294 and 0.3420 +/- 0.660 in young and old rat groups. In all rats, the correlation coefficient between the imbalance value of nNOS and Rho-kinase and the improvement of erectile function was 0.649, P < 0.01. In conclusion, this study suggested that impaired erectile function with ageing in SD rats be associated with the imbalance between nNO and Rho-kinase activity and Y-27632 could improve the erectile function in old SD rats through adjusting this imbalance.