Optimal dose of busulfan for depleting testicular germ cells of recipient mice before spermatogonial transplantation.

Successful spermatogonial transplantation requires depletion of the host germ cells to allow efficient colonization of the donor spermatogonial stem cells. Although a sterilizing drug, busulfan (Myleran), is commonly used for preparing a recipient mouse before transplantation, the optimal dose of this drug has not yet been defined. The present study investigated the effects of different doses of busulfan (10-50 mg per kg body weight) on survival rate, testicular mass and histomorphology, and on the haploid spermatids and spermatozoa of male BALB/c mice. The results suggest that a dosage of 30 mg kg(-1) is optimal for the ablative treatment with busulfan used to prepare the recipient mice. This dose results in an adequate depletion of the host germ cells for colonization of donor-derived spermatogonial stem cells and causes the lowest death rate of the animals.