Long-Term Survival of Autotransplanted Major Pelvic Ganglion in the Corpus Cavernosum of Adult Rats

Abstract

Neurogenic impotence is a common complication after radical pelvic surgery, irradiation or perineal trauma. Neuronal transplantation is a new frontier for treating neurological disorders. We investigated whether the major pelvic ganglion can survive and become functional after being implanted into the corpus cavernosum in adult rats. Adult male rats (13) were divided into 3 groups and sacrificed at 3 time points, namely 30 (4), 60 (5) and 90 (4) days. All rats underwent excision of the right major pelvic ganglion and left cavernous nerve. The right ganglion was implanted into the right crus of the penis. Electrostimulation was applied to the left major pelvic ganglion and cavernous nerve (1.5 mA.) and right crus (10 mA.) at sacrifice. The crural region and left ganglion were then excised for immunostaining of neuronal nitric oxide synthase (nNOS), protein gene product 9.5 and growth associated protein 43. Image analysis was used to calculate the area stained in pixels. Electron microscopy of the implanted area was performed to assess neuronal survival. Although the degree varied, all neuronal implants survived after transplantation. The response to electrostimulation was insufficient to produce erection. No difference was noted among the areas of nNOS staining when specimens from the 3 time points were compared. The area of expression of nNOS, protein gene product 9.5 and growth associated protein 43 was larger in the implanted area than in the surrounding cavernous tissue. Under electron microscopy most surviving implants showed normal ultrastructure, although areas of fibrotic replacement were seen in several implants. Our results show that the autotransplanted major pelvic ganglion expresses nNOS, protein gene product 9.5 and growth associated protein 43, and survived up to 90 days after implantation into the corpus cavernosum. Further studies with fetal neuronal tissue seem warranted.