Effect of partial bladder outlet obstruction on the histological structure of adult male rat urinary bladder and the role of l-arginine supplementation

Introduction Bladder outlet obstruction (BOO) is one of the most common urological problems in elderly men. l-Arginine, a precursor of nitric oxide synthesis, is thought to play an important role in the lower urinary tract function. Aim The aim of this study was to verify the effect of partial BOO on the structure of the urinary bladder in adult male albino rats and to test the possible protective role of l-arginine. Materials and methods Twenty-seven adult male albino rats were divided into three groups: rats in group I served as controls. Rats in group II were subjected to partial BOO. In group III, the obstructed rats were injected intraperitoneally with l-arginine (at a dose of 150 mg/kg body weight/day) for 6 weeks. Specimens were processed for H E and Mallory trichrome stains, desmin immunoreaction, and electron microscopic study. Morphometric results were statistically analyzed. Results Examination of the urinary bladder of obstructed rats showed an observable reduction in the urothelium thickness with focal sloughing of the mucosa as well as cytoplasmic vacuolation of some cells. Cellular infiltration and dilated congested blood vessels of the lamina propria were also encountered. Most smooth muscle cells were distorted with wide separation of muscle bundles and significant increase in the optical density of desmin expression. An increase in collagen fiber deposition was detected in the lamina propria. Ultrastructurally, the superficial urothelial cells showed electron-lucent vacuoles and large electron-dense granules, whereas the myocytes had irregular sarcolemmae. l-Arginine was able to prevent most of the observed alterations. Conclusion l-Arginine showed a potential protective role against the altered urinary bladder structure induced by partial outlet obstruction. Further physiological studies on the detrusor muscle under the effect of l-arginine are recommended.