EFFECTS OF X-IRRADIATION UPON THE DEVELOPING EYE AND THE MECHANISM FORMING MALFORMATIONS OF THE EYE

Abstract

1) Mice of the ddN and CF#1-JCL strain were subjected to a single whole body X-irradiations of 200R and 300R from day 7 to 12. In the ddN strain, abundant eye malformations were produced in those treated on day 8 and 11 while in the CF#1 strain the peak of the eye malformations produced was only on day 7. 2) Both the above strains of mice were subjected to the X-irradiation of 200R on day 11 and embryos were taken out 6, 12, 18, and 24 hours after the treatment. Thereafter, fetuses were also taken out at one day intervals. They were examined both grossly, by free hand razor blade sections, and partially under a microscope. 3) Microscopically, cellular necroses were evident in the primordial retina, especially in the internal layer of it. Debris eliminated by phagocytes continued 24 hours after X-irradiation in the ddN strain. However, such debris were continuously seen until 48 hours when the repair was completed. However, in the CF#1 strain, the involved eye presented an almost normal appearance 24 hours after the treatment. In the CF#1 strain, the eye in treated embryos was normally developed while in the ddN strain, the size of the eye was apparently small or the development was retarded suggesting sequencial microphthalmos. 4) Such divergences in the development from day 11 to 12 seemed to be caused by the difference in progress in the development in the primordial eye in the ddN strain. Further, the process in repair was also evidently retarded in the ddN strain. Conclusively, the above divergences may be caused by differences in developmental potencies between these two strains of mice employed.