Differentiation And Development Of Spermatogonia And Embryonic Stem Cells In Testicular Niche After Tansplantation

Testis, as reproductive organ in male mammals, composes of two main parts: seminferous tubules for generating sperm and interstitial tissue for androgen in order to keep the male environment. Testis has a relatively microenvironment, term as niche, there mainly are three types of cells- Leydig cells, Sertoli cells and spermatogonia in each stage of the sperm developing. In details, Leydig cells lies among the seminferous tubules, which can secret androgen to maintain the hormone environment in testis; Sertoli cells set up the blood-testis barrier by the tight junction to provide the special environment without immunity, which is very important for sperm forming, furthermore, Sertoli cells also can recognize stem sperm cells in testis and offer nourishment, supporting and regulating the differentiation of sperm. Recently, depending on the development of cytology technique, many scholars have deeply studies on differentiation and development of spermatogonia in the testis environment, and have been obtained some important results. Our experiments focus on differentiation and development of the spermatogonia after transplantation and how the Sertoli cells and donor spermatogonia recognized each other inside the testis. The experiments divided into two parts. The first part is the spermatogonia proliferation and differentiation, and the second part is constitute a embryonic stem cells with a Green fluorescent protein as marker in order to trace the behavior of spermatogonia after transplanting into recipient animals.At the first part of experiments, we transplant congeneric donor spermatogonia into the recipient and loaded them into the rete testis. In the advantage of the flow of the interior fluid, the exterior stem cells can go through every seminiferous tubule of recipient that the spermatogonia eliminated by busulfan treatment before the transplantation. Then, after 70days, spermatogenesis of the donor stem cells could be observed clearly and the male have reproduced progeny after mating with normal femal. This result demonstrates that the exterior stem cells can adversely go through the blood-testis barrier to arrive at the basemen, then proliferate and differentiate into mature sperms.Up to now, people could not clear out how the spermatogonium could go through theblood-testis barrier and arrive at basemen after transplanting into the recipient animals. We also could not answer the question that who will play a more important role in the recognizing procedure between the spermatogonia and Sertoli cells after transplantation. In order to clarify further, we design a kind of plasmid with gene of GFP (the green fluorescence protein) and pCR3.1 , and then, transfect it into the mouse embryo stem cells that be cultured in vitro to investigate the stem cells moving trend in the acceptor testis.Results of our experiment approve that variant stem sperm cells can proliferate and differentiate in the testis of recipient, at the same time, we set up the technique of transplanting of embryonic stem cell in our group. Using this kind of means, we could probe how the embryo stem cells differentiate in the testicular niche. This offer a very useful technique plantform to discover the relative relationship among the different types of cells in testis, the proceeding of spermatogeny and the transformation among the different sorts of adult tern cells.