Spermatogonia survival in young ram lambs following irradiation, Busulfan or thermal treatment

The impact of irradiation doses (0-15 Gy) delivered with high precision to the testis by a 6 MV photon beam was assessed by serial biopsies. Sertoli cell numbers were depleted by 90% at 3 weeks in 15 Gy treated testes. Spermatogonia were depleted 8 weeks after irradiation with 9 Gy, 12 Gy and 15 Gy. By 13 weeks, only in the 15 Gy treated testes were spermatogonia and Sertoli cell numbers lower. At 13 weeks testis atrophy resulted in 3/6 lambs irradiated with 12 Gy or 15 Gy. Irradiation of very young lambs clearly compromised testis function, thermal treatment was ineffective and busulfan treatment resulted in minimal effects.