CELL-GROWTH OF RAT LENS EPITHELIUM IN GALACTOSE-INDUCED CATARACTS

Cell growth of rat lens epithelium during galactose-induced cataract f ormation was examined in the present study using fluorescence cytophot ometry or proliferating cell nuclear antigen (PCNA) immunohistochemist ry, Six-week old male Sprague-Dawley rats were divided into 4 dietary groups according to galactose supplementation of the diet: 5%, 10%, 15 % and 25% galactose diet groups. Whole-mount preparations of rat lens epithelium were prepared. The nuclear content of epithelial cells was measured using fluorescence cytophotometry, and cells undergoing DNA s ynthesis (PCNA labeled cells) were detected using the PCNA immunohisto chemical staining method. The results of fluorescence cytophotometry s howed that cells containing tetraploid nuclei (4C cells) gradually inc reased in number. In the 5% galactose diet fed rats, the number of 4C cells peaked on the 9th day after the start of dietary galactose suppl ementation, the 7th day in the 10% galactose diet fed rats and on the 5th day in the 15% and 25% galactose diet fed rats. On each day that 4 C cells peaked, a large number of PCNA labeled cells were observed in the central zone of the epithelial cell layer. These results suggest t hat growth stimulation of lens epithelial cells depends upon the conce ntration of galactose in the diet and precedes changes in lens fiber.