[Cell kinetics of rat lens epithelium by cytofluorometric nuclear DNA determination]

The cell kinetics of rat lens epithelium was assessed by measuring the changes in the nuclear DNA contents during sugar cataract formation. Six-and-12-week-old Sprague-Dawley male rats were used and divided into the following groups: fed on normal chow, fed on 25% galactose diet, and fed on normal chow after 5 days on the 25% galactose diet. Every second day following the beginning of each chow feeding, lenses were extracted, and lens capsules with epithelial cells were obtained. After a few day's fixation in 4% paraformaldehyde dissolved in 0.1M phosphate buffer (pH 7.4), DAPI (4'6-diamidino-2-phenylindole)-stained lens epithelial cells were measured by fluorescence cytophotometry. The epithelia in the normal chow-fed rats contained many 2C and a few 4C nuclei. In the 25% galactose-fed rats, 4C nuclei increased gradually in number until the fifth day, and then decreases slowly day by day. Abnormal polyploid nuclei (8C) were observed in the 25% galactose-fed rats. 4C nuclei decreased rapidly after the diet reversal. These results indicate that galactose feeding caused higher DNA synthesis of rat lens epithelial cells and a higher possibility of abnormal cell division.