Leydig Cell Survival and Regeneration in Autografted Adult Mice Testis

Abstract

Background: The ectopic autografting of testis tissue is a promising approach towards studying testicular development, male germline preservation and restoration of male fertility. However the grafted adult testis is severely affected by ischemia and does not support spermatogenesis. The present study was a novel attempt to study the fate of testicular cells in adult testis subjected to autografting. Methodology: The testis of adult inbred Balb/c mice (6- weeks old) was autografted subcutaneously under the dorsal skin. These grafts were analyzed 1-, 2-, 4- and 8- week after grafting. The expression of cell-specific proteins was examined in testes by immunohistology. Seminal vesicle weight was determined to assess the functionality of Leydig cells. Results: Although the tubular architecture was progressively destroyed in autografts, the Leydig cell regenerated and their number progressively increased in grafts as indicated by CYP11A1, LHCGR and HSD3B immunohistochemically. Restoration of seminal vesicle weight of recipients exhibited Leydig cell functionality. Expression of PDGFRA, a stem Leydig cell (SLCs) marker, in 1- and 2- week grafts further confirmed Leydig cell regeneration. Absence of DDX4 staining from grafts at all collection time points suggested complete loss of germ cell population. Presence of Sertoli cells in grafts was confirmed by WT-1 immunohistology. Conclusions: These present study strongly indicate that Leydig cells regenerated de-novo in testis autografts however, germ cell population in grafts were unable to survive. The success of adult testis autografting in mouse containing functional Leydig cells can application to other vertebrates with testosterone deficiency and Leydig cell dysfunction.