Differentiations of transplanted mouse spermatogonial stem cells in the adult mouse renal parenchyma in vivo

Aim： Spermatogonial stem cells can initiate the process of cellular differentiation to generate mature spermatozoa, but whether it possess the characteristic of pluripotency and plasticity, similar to embryonic stem cells, has not been elucidated. This study was designed to evaluate the differentiation potential of spermatogonial stem cells into renal cells in vivo. Methods： Neonatal mouse spermatogonial stem cells were transplanted into mature male mice lacking endogenous spermatogenesis. The restoration of fertility in recipient males was observed. Spermatogonial stem cells were then injected into renal parenchyma of mature female mice to make a new extracellular environment for differentiation. Fluorescence in situ hybridization technology （FISH） was used to detect the expression of chromosome Y in recipient renal tissues. To determine the type of cells differentiated from spermatogonial stem cells, the expression of ricinus communis agglutinin, vimentin, CD45, and F4/80 proteins were examined in the renal tissues by immunohistochemistry. Results： The proliferation of seminiferous epithelial cells was distinctly observed in seminiferous tubules of transplanted testes, whereas no regeneration of spermatogenesis was observed in non-transplanted control testes. In transplanted female renal tissues, FISH showed a much stronger immuno-fluorescence signal of chromosome Y in the nucleolus of epithelial cells of the renal tubule and podocytes of the glomerulus. Conclusion： The spermatogonial stem cells were successfully purified from mouse testicles. This finding demonstrated that spermatogonial stem cells could not only restore damaged spermatogenesis, but were also capable of differentiating into mature renal parenchyma cells in vivo.