TESTICULAR SPERMATID AND EPIDIDYMAL SPERM HEAD COUNTS AS AN INDICATORFOR REPRODUCTIVE TOXICITY IN RATS

The testes of rats were exposed to a single soft x-ray irradiation at levels of 10, 25 and 63 Gy. Testicular and cauda epididymal weights an d their sperm counts were decreased at 7 weeks after the irradiation. Histologically, there was an evidence of interrupted spermatogenesis d ose-dependently. Animal mating trails, in which irradiated males were mated with untreated females revealed a slight increase in early stage of postimplantation loss at as low as 10 Gy. There were increases in preimplantation and early stage of postimplantation losses in the grou p of irradiated at 25 Gy. Infertility occurred in irradiated males at 63 Gy. The effects of irradiation were more severe on the sperm count parameters than on reproductive organ weights, histological examinatio n and reproductive status. The testicular spermatid and epididymal spe rm head counts are considered to be useful indicators to detect quanti tatively the adverse effects on spermatogenesis.