Models of in vitro spermatogenesis

Abstract

Understanding the mechanisms that lead to the differentiation of male germ cells from their spermatogonial stem cells through meiosis to give rise to mature haploid spermatozoa has been a major quest for many decades. Unlike most other cell types this differentiation process is more or less completely dependent upon the cells being located within the strongly structured niche provided by mature Sertoli cells within an intact seminiferous epithelium. While much new information is currently being obtained through the application and description of relevant gene mutations, there is still a considerable need for in vitro models with which to explore the mechanisms involved. Not only are systems of in vitro spermatogenesis important for understanding the basic science, they have marked pragmatic value in offering ex vivo systems for the artificial maturation of immature germ cells from male infertility patients, as well as providing opportunities for the transgenic manipulation of male germ cells. In this review, we have summarized literature relating to simplistic culturing of germ cells, co-cultures of germ cells with other cell types, especially with Sertoli cells, cultures of seminiferous tubule fragments, and briefly mention the opportunities of xenografting larger testicular pieces. The majority of methods are successful in allowing the differentiation of small steps in the progress of spermatogonia to spermatozoa; few tolerate the chromosomal reduction division through meiosis, and even fewer seem able to complete the complex morphogenesis which results in freely swimming spermatozoa. However, recent progress with complex culture environments, such as 3-d matrices, suggest that possibly success is now not too far away.

Three Testis-Specific Paralogous Serine Proteases Play Different Roles in Murine Spermatogenesis and Are Involved in Germ Cell Survival During Meiosis1

“…Several methods for in vitro spermatogenesis have been published. For most of these, meiosis successfully proceeds to the spermatid stage [56][57][58][59]. Because the Prss/Tessp proteins were present in spermatocytes and spermatids, organ culture was a suitable system to investigate their functions.…”

Study of Tnp1, Tekt1, and Plzf Genes Expression During an in vitro Three-Dimensional Neonatal Male Mice Testis Culture

“…In addition to Tnp1 and Tekt1, the essential role of Plzf in the maintenance of spermatogonial stem cells has been revealed previously [12] . The study of these proteins and those involved in spermatogenesis is very important to the concept of in vitro spermatogenesis [13] . In the present study, we attempted to assess whether Tnp1, Tekt1, and Plzf, which have essential roles in spermatogenesis, can be expressed during organ culture of testis.…”

Pesticide Exposures Induce Male-Mediated Reproductive Toxicity: A Review

“…The reproductive system involves dramatic cycles of tissue growth and degeneration. The spermatogenesis is no exception to this generalised phenomenon which involves mitosis, meiosis, cellular differentiation of spermatogonia into mature spermatozoa and apoptosis (Hunter et al, 2012). Additionally, an entire hormonal stimulation from the hypothalamus and pituitary gland are required for spermatogenesis as well as the perfect function of the testes (Gabrielsen & Tanrikut, 2016).…”