Study on Transplanting Germ Like Cells Differentiated from Embryonic Stem Cell into Mouse Seminiferous Tubules

ObjectiveTo investigate whether germ like cells isolated from embryoid body formed by mouse embryonic stem cells could survive and initiate spermatogenesis in seminiferous tubules of adult mice.MethodsSSEA-1+ cells were isolated from embryoid bodies prepared from mouse EGFP-ES cells, after retinoic acid treatment, the cells were detected for the expression of alkaline phosphatase, Rnh2, Stella, fragilis, Texl4, Sry, Hsp90-α, Stra8 and inte grin a6, and then, the cells were transplanted into seminiferous tubules of busulfan-treated adult mice.ResultsSix days after retinoic acid treatment, alkaline phosphatase expressing cells could still be found in embryoid body (EB) derived cells, indicating the existence of retinoic acid-resistant primordial germ cells. When the SSEA-1+ cells isolated from embryoid bodies were stimulated with retinoic acid for 6 days, some of these cells expressed cell markers of Hsp90-α, Stra8 and inte grin α6, resembling the expression profile of spermatogonial stem cells. Forty-five days after cell transplantation, a little amount of GFP-expressing cells attached to the basement membrane of seminiferous tubule and formed small colonies; Three months later, these cells started amplification in the form of cell chains with varied length, and moving towards the lumen of the seminiferous tubules. Five months after the transplantation, multilayered cell mass was found in seminiferous tubules of two, out of four recipient mice. There was no GFP-expressing cells existed in non-cell-transplanted seminiferous tubules.ConclusionIn our study, although full-termed spermatogenesis was not observed in all of the recipients, the results did indicate that the embryoid body contains germ like cells, and these cells can survive and initiate amplification in seminiferous tubules of adult mouse.