Regeneration of spermatogenesis by grafting testicular tissue or injecting testicular cells into the testes of sterile mice: a comparative study

ObjectiveTo make a comparison between two different approaches—spermatogonial stem cell transplantation and intratesticular grafting, for preservation and reintroduction of spermatogonial stem cells.DesignProspective experimental study.SettingAcademic medical center and teaching hospital.Patient(s)N/A.Intervention(s)Intratesticular transplantation, histologic evaluation of testes.Main Outcome Measure(s)Testicular weight, amount of green fluorescence in the testis, and immunostaining for green fluorescent protein.Result(s)In a first experiment donor-derived spermatogenesis was found in 65% of the injected testes (41.8 ± 72.2 mm) compared with 75% of the testes (122.1 ± 45.6 mm) after tissue grafting. In the second series of experiments complete spermatogenesis was found in 75% of the testes after fresh grafting (93.8 ± 21.8 mm) compared with 88% after frozen-thawed tissue grafting (84.8 ± 45.6 mm).Conclusion(s)Both approaches show that spermatogonial stem cells can successfully be introduced to the testis resulting in spermatogenesis. Tissue grafting produced a larger mean donor colony length and there was no significant difference between colonization efficiency using either fresh or frozen-thawed grafts. In a future clinical setting, grafting would be a simple and efficient way for reintroducing stem cells to the testis.