Spermatogonial stem cells in the bull

Abstract:

In the testis a complex process, called spermatogenesis, generates millions of spermatozoa per day. At the start of this process there are spermatogonial stem cells (SSCs) that have the ability to divide either into new stem cells (self-renewal) or daughter cells committed to develop into spermatozoa (differentiation). SSCs are the only cells among the adult stem cell systems capable of transmitting genetic information to future generations. This offers possibilities for in vitro SSC manipulation for instance with the goal of transferring relevant genes across bovine herds. As bovine species have a long generation interval, a system through which genes could be delivered to cattle through SSCs would prove effective and time-saving. SSCs and the first generations of differentiating spermatogonia are morphologically indistinguishable and are called type A spermatogonia. Therefore, we started with finding out at which age type A spermatogonia could be best isolated. We first investigated the onset of spermatogenesis in Brahman bulls, a widely used breed of Asian origin, and compared our results with the available information on European breeds. The best time to obtain A spermatogonia from European and Asian breeds was found to be the age period between the start of spermatogenesis (appearance of the first spermatogonia) to the age at which the first spermatocytes are formed. During this period the purity of the spermatogonia is optimal since no other differentiating germ cells have yet appeared. We then developed a culture system to propagate these A spermatogonia. Using StemPro medium and adding a number of growth factors we could …

Año de publicación:

2009

Keywords:

Fuente:

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