LIGHT-MICROSCOPIC AUTORADIOGRAPHIC STUDY ON DNA-SYNTHESIS IN AGING MICE CORNEAS

The morphological change and DNA synthesis of the aging mice corneal c ells were investigated by light microscopic radioautography after inje ction of tritiated thymidine. The result showed that the incorporation of tritiated thymidine in corneal cells changed with aging. The sites of tritiated thymidine incorporation were located in the epithelium f rom postnatal day 19 to 1 year after birth, in the stroma and endothel ium from prenatal day 19 to postnatal day 8 only. The labeling index i n the epithelial cells reached its highest value at 1 month after birt h. Labelled stromal and endothelial cells reached their peaks simultan eously on the third day after birth and disappeared completely from po stnatal 1 month onwards. The thickness of the cornea increased obvious ly at one month and there were no notable morphological change thereaf ter. Our investigation provides for the first time a systematic study on the age-related changes of DNA synthesis and construction in the ag ing mice corneas.