Spermatogonial Stem Cell Transplantation and Culture - Male Germline Stem Cells Developmental and Regenerative Potential - page 109

Fig. 5.1 Procedure for transplantation of testis cells. (a) Donor testes carrying a transgene are
digested resulting in a single cell suspension. (b) These cells can be enriched for SSC using methods
such as differential plating, MACS, and FACS, and can be cultured using appropriate conditions.
(c) Testis cells are injected into the testis of a recipient animal that is immunologically compatible
to the donor and that has little to no endogenous spermatogenesis due to natural mutation of
experimental treatment. (d) During the subsequent 2-5 months, donor SSCs colonize the recipient
testis and initiate donor-derived spermatogenesis. If the donor was transgenic for a colorimetric
marker such as LacZ or GFP, testes can be removed and examined using appropriate
techniques to quantify colonies of spermatogenesis, each of which is derived from a single SSC.
(e) The recipient male can also be mated with a fertile female and produce donor derived progeny.
(f) Donor-derived progeny can be identified using appropriate techniques. It is possible that
recipient-derived progeny are also produced owing to endogenous spermatogenesis. This image
was used with permission from Brinster ( 2002 ) © American Association for the Advancement of
Science
of the germline and reinitiation of spermatogenesis in prepubertal individuals
undergoing chemotherapy. SSC transplantation would also be very useful in agri-
culture and for the conservation of endangered species. Thus, preservation of the
germline of valuable animals and transplantation of these cells into less valuable
recipients resulting in donor-derived spermatogenesis could increase the quality of
agricultural products and contribute to the preservation of endangered species. Of
particular interest from a human clinical, agricultural, and biotechnological view-
point is the potential to generate transgenic individuals by manipulation of the male
germline. This technique would be useful for gene therapy of the male germline to
correct mutations that affect spermatogenesis in infertile individuals or to remove
deleterious genes from the gene pool in animals and potentially humans.
Additionally, transgenic animals could be generated that express economically
valuable proteins in meat or milk. Indeed, the groundwork for many of these appli-
cations has been established in rodents and attempts have been made to extend
these techniques to other more economically valuable species.