Background
Defects of the male urogenital structures are associated with impaired sexual function and a significantly reduced quality-of-life. Modern reconstructive methods employ autologous tissue-based reconstructions and implant placement to reconstruct a functional phallus. Penis transplantation has been successfully employed in the recent past and represents an exciting avenue for restoration of male urogenitalia and function by using “like-with-like” tissue. This animal model is designed to fill a critical void as only little is known on the immunology of these unique tissue grafts.
Methods
In male 8-week old BN & Lewis rats the penis was dissected to design a penile graft based on the internal pudendal artery and dorsal penile vein including the skin of the prepuce. The non-suture cuff technique was employed to perform end-to-end anastomosis of the graft vessels to the recipient inferior epigastric vessels. Syngeneic and allogeneic transplants were performed Native and graft penile tissue were obtained at various time points for histologic analysis.
Results
Graft design yields suitable caliber and length of graft vessels at the radix of the penis. Anastomosis of the dorsal penile vein and the distal internal pudendal artery at the bifurcation into dorsal and deep penile arteries ensures optimal perfusion of the entire superficial and deep graft tissues. The non-suture cuff technique allows for successful microvascular anastomosis by a single surgeon in an average of 25 hours. Long-term graft survival (>30 days) was observed in syngeneic transplants (N = 3). To date, allogeneic transplant combinations from BN to Lewis rats have been performed and tissues have been harvested for analysis at various time points (ie POD 3, 5, 7, 9, 11; N = 5).
Conclusion
We have been able to establish a robust and reproducible murine model to study the unique immunobiology of urogenital tissue in the context of reconstructive transplantation. The design of the graft ensures optimal vascular perfusion of superficial and deep penile tissues. Heterotopic inset further allows for visual monitoring of graft viability, while the native penis serves an optimal control. The graft design includes the dorsal penile nerve and may thus be a platform for studies on erectile tissues and function.