Viability of homologous and heterologous subcutaneous transplantation of fresh germ cells in rabbits

OBJECTIVE: This study aimed to compare heterologous to homologous transplantation of fresh ovarian germ cells in rabbits. METHODS: Twelve female white New Zealand rabbits (Oryctolagus cuniculus) were randomly numbered and submitted to bilateral oophorectomies. The ovaries from the six odd-numbered rabbits were dissected and cortical germinal tissue was digested in collagenase type 1 to obtain six solutions containing stromal and germ cells, which were injected in the abdominal region of the odd-numbered rabbits themselves (homologous transplantation) and of the even-numbered rabbits (heterologous transplantation) off immunosuppression. Sixty days after transplantation, the tissue around the transplanted region was excised, processed and sent to histological analysis with hematoxylin-eosin staining and Bcl-2 immunohistochemistry to verify the presence and viability of the transplanted cells. RESULTS: The analyzed specimens contained ovarian stroma, while follicular cells were found in 66.6% of the homologous and in 60% of the heterologous transplant specimens. Mild inflammatory reaction was observed in all heterologous specimens, and in only one (16.7%) of the homologous specimens. However, this inflammatory reaction was not so intense as to cause the death of the implanted cells. Except for the specimens from rabbits 7 and 8, all specimens were stained for Bcl-2, indicating that most of them were viable. CONCLUSIONS: The results of this study supported the viability of heterologous transplantation of fresh ovarian germ cells. However, more studies are required to further our understanding and improve the germ cell separation technique.