Expression of Nitric Oxide Synthase (NOS) in Rat Bladders Subjected to Short-term Partial Outlet Obstruction

Abstract

Purpose: Nitric oxide synthase (NOS) is an important enzyme in the production of nitric oxide (NO). The constitutive type (cNOS) is expressed in the normal physiologic state, and the inducible type (iNOS) in expressed in the active immune state. cNOS is divided into an endothelial type (eNOS) and a neuronal type (nNOS). eNOS affects blood vessels, while nNOS affects nerve fibers. In the present study, we evaluated the expression of eNOS and nNOS in rat bladders with short-term partial outlet obstructions. We presupposed that NO is responsible for prolonged micturition problems after partial outlet obstruction. Materials and Methods: Specific pathogen-free Sprague-Dawley rats weighing 250-300g were used for the study. Individual bladders were obtained from sham-operated control rats (n=5) and from experimental rats at 12 hours and 1, 2, 3, and 7 days after partial urethral obstruction (n=25). eNOS and nNOS were detected using immunochemical staining and analyzed with confocal microscopy and an image analyzer. Results: eNOS and nNOS expression were detected in both the control group and in the group with partial outlet obstruction. The expression of eNOS showed a sharp increase at 3 days after obstruction and returned to normal at 7 days. The expression of nNOS was not significantly different between the two groups. Conclusions: In this study, we showed that eNOS increases in the rat bladder after partial outlet obstruction. This finding suggests that overproduction of NO may be the result of ischemic injury sustained during partial bladder outlet obstruction. (Korean J Urol 2008;49:622-626) 󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏