Cavernous nerve reconstitution with the use of bone marrow stem cells and erectile function evaluation: an experimental animal study

Objective: To assess the influence of adult stem cells from bone marrow of rats in the regeneration of cavernous nerve, taking the return of erectile function as a parameter in animals subjected to the apomorphine-induced test of erection. Methods: Forty-eight male Wistar-EPM rats, aged between nine and ten weeks, and weighing approximately 250 g were used. They were randomly divided into four study Groups containing 12 animals each, as follows: Group I: surgical exposure of the cavernous nerves bilaterally without injury; Group II: bilateral surgical injury of the cavernous nerve of approximately 3 mm, without reconstruction; Group III: bilateral surgical injury of the cavernous nerves of approximately 3 mm, and bilateral reconstruction with silicone guiding tubes containing saline solution inside; Group IV: bilateral surgical injury of the cavernous nerves of approximately 3 mm, and bilateral reconstruction with silicone guiding tubes filled with adult stem cells. Four weeks after surgery, the animals were injected with apomorphine for induction of erection. Rresults: In Group I there was complete erectile response in all animals (100% – 12 out of 12). On the other hand, none of the animals in Group II presented erection after the use of apomorphine. Five of the twelve animals of Group III (41.7%) and nine of the 12 animals of Group IV (75%) had erections after the stimulus. When we compared the frequency of restoration of erection in the four Groups, Group IV was shown to have a similar performance to Group I (p = 0.217), while Group III animals had a frequency of erections inferior to those in Group I (p = 0.005). Moreover, comparison of results of Groups III and IV versus Group II showed that the frequency of erections was statistically higher in the first two Groups (p = 0.037 and p < 0.001, respectively). Finally, Group IV presented a tendency to a larger number of erections when compared to Group III (75 versus 41.7%) but this difference was not statistically significant (p = 0.098). Cconclusion: This study shows that adult stem cells from bone marrow, filling silicone guiding tubes, may promote the regeneration of cavernous nerves and restore erectile function in an animal model.