To determine whether the rat develops corporal veno-occlusive dysfunction (CVOD) during the aging process.

We divided male Fisher 344 rats into four groups with 5 to 8 rats in each group. Group 1 rats were 5 months old and not orchiectomized (young intact); group 2 were 5 months old and had undergone castration (control CVOD); group 3 were 24 months old and not orchiectomized (aged intact); and group 4 rats were 24 months old, nonorchiectomized rats who had undergone deep dorsal vein (DDV) ligation (aged ligated). Serum testosterone was measured, and dynamic infusion cavernosometry and cavernosography (by dual-energy x-ray absorptiometry scan) were performed.

Compared with the young intact animals, the aged intact rats had a 73% reduction in testosterone, a 30% reduction in intracavernosal pressure after papaverine injection, and an 84% and a 44% increase in the maintenance and drop rate, respectively, during dynamic infusion cavernosometry. The extent of CVOD as measured by cavernosometry in the aged rats was similar to that in the young castrated rats, but was more pronounced when measured by dynamic infusion cavernosometry. Cavernosography confirmed that the aged rats had venous leakage primarily by way of the DDV. By applying DDV ligation, distal penile engorgement occurred, showing that a small venous leakage occurred primarily by way of the cavernosal veins.

These data have demonstrated that CVOD occurs in the aged rat, mainly through the DDV. This supports the concept that the aged rat is an appropriate animal model to study erectile dysfunction associated with CVOD.