THE EFFECT OF X-RAYS OF 1000R ON MALE GERM CELLS IN THE MOUSE, WITH PARTICULAR ATTENTION TO THE DIFFERENCE IN X-RAY SENSITIVITY OF SPERMATOGONIA
1970 年 45 巻 4 号 p. 239-254
詳細
1970 年 45 巻 4 号 p. 239-254
The change of each spermatogenetic cell population in mice from 6 hours to 14 weeks after irradiation of 1000R was investigated quantitatively and histologically, directing particular attention to the difference in X-ray sensitivity of spermatogonia.
The decrease in spermatogenetic cell populations after irradiation occurs according to the order of their developmental stages showing the higher sensitivity of spermatogonia to X-rays: spermatogonia begin to decrease with a high incidence of necrosis at 12 hours after irradiation and show a remarkable loss at the 3rd day. At the 12th day spermatocytes have disappeared completely. The depletion of spermatids and spermatozoa occurs respectively at the 3rd and the 4th week showing their resistance to X-rays of high dosages.
The present studies, in comparing the sensitivity of spermatogonia, indicate that intermediate and type B cells are more sensitive to radiation than type A cells. Further, it seems to support the view that a few spermatogonia of type A showing heterogeneous sensitivity survive after irradiation and repopulate new spermatogenetic cell elements.
Although a large number of spermatogonia degenerate immediately after irradiation showing necrosis, some spermatocytes become abnormal spermatids, as revealed by signet-ring cells, multinucleated cells and unusual size of nuclei, suggesting the formation of abnormal spermatozoa.
An occurrence of Sertoli cells and interstitial cells in considerable numbers in severely damaged testes, suggested their high resistance to X-rays. Their apparent increase seems to be a relative increase due to the shrinkage of seminiferous tubules accompanying with the depletion of the tubular constituents.
The rate of decrease of the tubule-diameter after irradiation depends on the radiation dose. From this fact, the tubule-diameter curve may play a role of comparing radiation effects.
