OBJECTIVESTo investigate the effect of diabetes mellitus on nNOS-containing nerve fibers in rats corpus cavernosum.

METHODSHealthy male Sprague-Deuley rats (n = 34) were divided into two groups randomly, the sixth (n = 17) and eighth groups (n = 17). Eleven of severteen rats wree intraperitoneal injection with streptozotocin (STZ) to induce experimented model of diabetes medilus in each group. The other were injected with citrate buffer as control. Injected with apmorphine at sixth and eight week, penile erection in diabetic and control groups were observed and noted. The expression of nNOS-positive containing nerver-fibers in corpous cavernosum were examined with streptavidin-peroxidase immunohistochemistry (SP method).

RESULTSThe erection rate of penile diabetic mellitus decreased compared to that in controls (P < 0.01). The erection rate of two diabetic groups were 37.5% and 14.3%, respectively, with significant difference (P < 0.05). The controls were all 100%. The significant changes of nNOS-containing never fibers were observed in the two diabetic groups. The numbers of nNOS-containing nerver fibers in the corpus cavernosum in the two diabetic groups were (37.00 +/- 6.76) and (28.00 +/- 5.29), respectively, with significant difference compared to each other (P < 0.05). In the two controls, the fibers were (83.00 +/- 3.22) and (81.00 +/- 3.61), respectively. The fibers in diabetic groups were less than those in controls (P < 0.01).

CONCLUSIONSThe erectile function of rats and the number of nNOS-positive containing nerve fibers is affected seriously by diabetes mellitus and it is positively correlated to the duration of diabetes mellitus. The decreasing of nNOS-positive containing nerve fibers may be one of the mechanisms of diabetic erectile dysfunction.