Abstract
Abstract: :
Purpose:Zinc (Zn) is an essential trace element. Zn metalloenzymes are distributed widely in the rat lens. It is not known whether Zn is necessary to maintain the normal structure of the rat lens. The purpose of the present study is to examine the early pathologic changes in the lens in Zn-deficient rat. Methods: Normal 21-day-old male Wistar Kyoto rats were fed a Zn-deficient diet containing 0.007 mg Zn per 100g of diet and all other nutrients and distilled and deionized water. As controls, normal 21-day-old male Wistar Kyoto rats were given free access to usual commercial rat pellets containing 4.7 mg Zn per 100g of diet and all other nutrients and distilled and deionized water. The Zn-deficient and control rats were killed at 7 weeks of age. The lenses were examined with a scanning electron microscope (SEM) (Hitachi S-2360N). Results:At 7 weeks of age, Zn-deficient rats had significantly lower body weights and serum Zn levels than normal rats. Slit-lamp microscopy disclosed no opacity in the lens cortex and nucleus. SEM disclosed a regular lens fiber arrangement with no substantial changes in fiber structure. The lens fibers were wide and showed well-developed. edge processes and ball-and-socket junctions, but the processes were irregular in shape and size. Conclusion:Zn deficiency induced irregular sizes and shapes of lens fiber processes in rats. These may the an initial changes in cataract formation.
Keywords: 506 pathology: experimental • 472 microscopy: electron microscopy • 316 animal model