A shorter interval between irradiation of recipient testis and germ cell transplantation is detrimental to recovery of fertility in rams

Abstract

The objective of the current study was to identify an optimal time period for donor cell transplantation after irradiation in sheep. The testes of recipient rams were treated with a single dose of 15 Gray (Gy) irradiation followed by germ cell transplantation either 3 or 6weeks later. Transplantation of donor cells at 6weeks after irradiation resulted in production of donor sperm by all five recipient rams compared with 4 of 11 rams transplanted at 3weeks. Rams transplanted 3weeks post-irradiation appeared to show reduced libido and fertility. Two rams produced sperm with low motility (<20%) and two other rams were azoospermic. More than 1year after cell transfer, there were heavy infiltrates of CD45-positive cells and more fibrous tissue in 9 of 14 recipient testes (seven rams) that received cells 3weeks after irradiation. Taken together, these results suggest that the interval between irradiation of recipients and germ cell transplantation affects the success rate of the procedure, with a 6-week interval preferable. The elevated inflammatory/immune reaction may be responsible, at least in part, for the reduced fertility and low libido observed in the rams that received cells 3weeks post-irradiation. © 2010 The Authors. International Journal of Andrology © 2011 European Academy of Andrology.