Postnatal mirex cataractogenesis in rats: Lens cation balance, growth and histology

Abstract

The effects of lactational mirex exposure on postnatal lens cation balance, lens growth and histology were examined in this study. Pregnant Long Evans rats were allowed to give birth, and litters were culled to eight individuals. Dams were intubated with 10 mg kg-1 day-1 mirex on days 1-4 postpartum. Pups were killed at 6-14 days of age, and lenses were removed, examined for opacities, weighed, and assayed for K+ and Na+ concentrations. Cataracts occurred in 71·0% of all treated litters and 58·1% of all treated individuals. Histologically, lenses from treated pups showed anterior and posterior cortical vacuoles by 8 days of age, greatly swollen lens fibers by 10 days of age, and areas of cell degeneration by 12-14 days of age. Lens K+:Na+ ratios were lower in treated groups on days 8-14 after birth, in both clear and cataractous lenses, and cataractous lenses were significantly higher in water content. Lens: eye weight ratios were not affected. The results of this study indicate that mirex-induced postnatal cataracts are due to lens degeneration subsequent to fiber cells swelling. © 1984.