The incidence of impotence in diabetic patients has been reported to be about 50 percent. The erectile dysfunction is related to penile autonomic nerophathy and/or microangiopathy. In this study, rats with streptozotocin(STZ)-induced diabetes
were
used
to examine the pathogenesis of diabetic impotence and to prove the usefulness of this model for such study.
Diabetic impotence was evaluated by the mating test. The changes of the dorsal arteries and the cavernosal and cavernous nerves containing norepinephrine(NE), vasoactive intestinal polypeptide (VIP) nad acetylcholiesterase(AChE) were examined
using
histological, immunohistochemical and morphometric techniques at 4, 8 and 12 weeks after induction of diabetes. The following results were obtained:
1. The weights of the diabetic rats remained significantly lower than those of control rats throughout the experimental period.
2. At the12th week of diabetes, the mating rate of diabetic rats was significantly reduced.
3. Dorsal arteries of diabetic rats showed reduced internal elastic membranes and thinned walls. Within the corpora cavernosa, the mass of smooth muscle was reduced, intercommunicating vascular spaces were enlarged and wavy collagen bundles were
thin
and sparse. A significant reduction in the number of myelin sheaths and nuclei was observed in the cavernous nerves of diabetic rats from week 4 after diabetes induction.
4. A significant reduction in the density of AChE-and VIP-immunoreactive nerves was observed in the cavernous nerves of diabetic rats from week 8 after diabetes induction. However, no change was observed in the density of NE-immunoreactive
nerves.
5. There was marked thickening of the basement membrane of dorsal arteries, Schwann cells and perineurial cells of diabetic rats from week 8 after diabetes induction.
From the above results, experimental diabetes resulted in microangiopathy and neuropathy in which cholinergic and VIP ergic nerves, but not adrenergic nerves, were reduced, which may be regarded as important causes of diabetic impotence. It is
suggested
that rats with STZ-induced diabetes are suitable for the study of diabetic impotence.
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