Effect of Insulin and Testosterone on Damage to the Erection-Related Nervous System in Experimentally Diabetic Rats

Kang, Dong Il; Choi, Sung Hyup; Min, Kweon Sik

Abstract

PURPOSE
Diabetic autonomic neuropathy can cause organic sexual dysfunction in men. The possibilities of preventing or inhibiting erection-related nerve damage by early administration of insulin and testosterone were investigated in the streptozotocin(STZ)-induced diabetic rat model.
MATERIALS AND METHODS
Forty Sprague-Dawley rats were divided into normal control and four experimental diabetic groups(untreated, insulin treated, testosterone treated, and insulin and testosterone treated). The pathologic effects were evaluated by nicotinamide adenine dinucleotide phosphate diaphorase staining of nitric oxide synthase(NOS)-containing nerve fibers and neurons of the corpus cavernosum, the dorsal nerve, and the pelvic ganglion.
RESULTS
The NOS-containing nerve fibers and neurons in the corpus cavernosum, dorsal nerves, and pelvic ganglia were decreased significantly in untreated diabetic rats. In the insulin- and/or testosterone-treated diabetic rats, a significant increase was observed compared with the untreated diabetic rats. In the number of axons in the dorsal nerves, the same results were demonstrated as for the NOS-containing nerve fibers. In all groups, there was a significant correlation between the ratio of NOS-containing neurons in the pelvic ganglia and the numbers of NOS-containing nerve fibers in the corpus cavernosum(r=0.641, p<0.05).
CONCLUSIONS
Early administration of insulin, testosterone, or both may prevent or ameliorate neural damage related to sexual dysfunction in a STZ-induced diabetic animal model.