Feasibility study of transplantation of penile corpus cavernosum and major pelvic ganglion in renal subserous region

OBJECTIVE: To study the feasibility of transplantation of normal rat penile corpus cavernosum and major pelvic ganglion (MPG) into the renal subserous region of a Nu/Nu mouse based on allograft technology. METHODS: Penile corpus cavernosum and MPG, harvested from Sprague-Dawley (SD) rats under sterile condition, were transplanted underneath the kidney capsule of Nu/Nu mice through the microsurgery instruments and surgery microscope. The histopathologic changes and cellular proliferation in the transplanted penile corpus cavernosum and MPG were then analyzed at the end of 1week and 4 weeks after transplantation. Histological staining and immunohistochemical staining were used to evaluate the main outcome measures. RESULTS: After 1 week, the tissue morphology of the transplanted corpus cavernosum underneath the kidney capsule of Nu/Nu mice was consistent with normal penile corpus cavernosum, and blood could be observed in the penis cavernous sinus of the graft; after 4 weeks, the mophorlogy of the tranplanted corpus cavernosum near the kidney was consistent with normal penile corpus cavernosum, while fibrosis was noteworthy in the graft away from the kidney, but blood could still be seen in the penis cavernous sinus. After 1 week, the tissue morphology of the transplanted MPG was consistent with normal MPG, multiple islet-like cell clusters could be seen in the transplanted MPG in the renal subserous region, and angiogenesis could be observed near the kidney; after 4 weeks, a network of blood vessels was clearly visible away from the kidney, and islet-like cell clusters were still clearly observed in the transplanted MPG. In addition, ki67 positive cells were observed in the transplanted penile corpus cavernosum and MPG after 4 weeks of transplantation, which indicated that there was still cell proliferation activity in the grafts. CONCLUSION: The transplanted corpus cavernosum and MPG underneath the kidney capsule of Nu/Nu mice could survive at least 4 weeks. Moreover, the inner structure of the transplanted corpus cavernosum and MPG was close to the normal tissue. The underlining mechanism may be related to the local microenvironment underneath the kidney capsule of Nu/Nu mice and the neovascularization in the transplanted grafts.