Cellular debris and ROS in age-related cortical cataract arecaused by inappropriate involution of the surface epithelial cells intothe lens cortex

[摘要] Purpose: To quantify changes in the lens epithelial cells andunderlying lens cortex responsible for age-related cortical cataract(ARCC) in the rat.Methods: Freshly isolated lenses were stained vitally for DNA withHoechst 33342. Reactive oxygen species (ROS) and mitochondria werevisualized and quantified by dihydrorhodamine 123 (DHR). Thefluorescence was quantified using Laser Scanning Confocal Microscopy(LSCM) of vitally stained lenses. Cortical DNA was verified as such byDNAse I digestion. Cataract reflections were determined from digitalizedimages of light reflections taken with a low magnification lightmicroscope, or with the LSCM.Results: The anterior surface epithelia of old rat lenses were fullof gaps and ragged in appearance with a decrease of over 50% in lensepithelial cell (LEC) density. The surface LECs were frequently seen tohave involuted into the cortex at inappropriate sites, forming depositsfull of DNA, nuclear and mitochondrial debris, and abundant ROS. Theseinvolutions frequently originated near open gaps in the surfaceepithelia, where they appear to have detached from the capsularmembrane. Cortical cataracts in the rat lenses were seen to co-localizewith these LEC involutions, as had been seen previously in mice withARCC.Conclusions: ARCC in rats co-localized with inappropriateaccumulations of nuclei, mitochondria, DNA, and expression of ROS indebris filled foci. These were the result of both involution of surfaceLECs into areas of cortical ARCC, and by an extension of the normal bowregion deep into the anterior and posterior of cataractous lenses. Theseresults were in complete agreement with our previous studies on ARCC inmice.

[学科分类] 生物化学/生物物理