MORPHOLOGICAL-STUDY ON GLUCOCORTICOID-INDUCED CATARACT IN DEVELOPING CHICK-EMBRYO

Nishigori et al. reported a transient cataract model after ad minister ing glucocorticoid to a 15-day-old chick. Biochemically, the mechanism of onset of this cataract was thought to be related to damage caused by the formation of oxi dative stresses and by a protein-water phase s eparation. There appear to be no reports on changes in the fine struct ure. After hydroocortisone succinate sodium was administered to 15-day -old chick embryos, the lenses were removed at 12, 24, 30, 48, 72 and 96 h and put in 4% glutaraldehyde The specimens were examined by light , transmission and scanning electron microscopy. Twelve to 24 h after administration to chick embryos, lens fibers containing electron-dense cytoplasm began to appear in the bow area of the equator and were sti ll present thereafter. Thirty to 48 h after administration, numerous v acuoles of varying sizes began to appear in the lens in sites correspo nding to the opaque region. These vacuoles, ranging from 2 to 8 mum in diameter, were distributed in the intercellular spaces between the le ns fibers. The vacuoles had disappeared by 96 h after administration, but during that period, the height of the epithelial cells in the equa torial region and the elongation of the equatorial lens fibers had bec ome irregular. Transient opacity was due to the presence of vacuoles o f various sizes, occurring in the intercellular space between the lens fibers around the lens nucleus. Moreover, the effect of glucocorticoi d administration was noted in the lens epithelium and the lens fibers in the equatorial region.