Effect of x-rays on spermatogenesis in inbred strains of mice

The effect of x-ray irradiation with doses of 0.5 Gy and 3 Gy on the number of the spermatozoa and the structure of seminiferous tubules in the inbred strains of mice KE, KP, CBA/Kw and C57/Kw was investigated on the 28th day following irradiation. Differences in the radiosensitivity between the studied strains were found. C57/Kw males revealed the highest resistance to x-rays as manifested by the absence of significant differences in the number of the spermatozoa and the relative frequency of tubules at stages VII-XII of the spermatogenetic cycle between control animals and those irradiated with 0.5 Gy. The same dose caused a decrease in the number of spermatozoa and altered the frequency of the particular stages in the other strains. Following irradiation with 3 Gy the number of spermatozoa in the C57/Kw strains declined but still was significantly higher than in the other strains. The latter dose brought about an inhibition of the spermatogenesis in all the studied strains to the extent of degeneration of the seminiferous tubules which contained no more than occasional spermatogonia. The percentage of such degenerated tubules in the C57/Kw strain was, however, as low as 14.5%, whereas it approximated 50% in the KE and KP strain.