Cellular debris and ROS in age-related cortical cataract are caused by inappropriate involution of the surface epithelial cells into the lens cortex.
OBJECTIVE
To quantify changes in the lens epithelial cells and underlying lens cortex responsible for age-related cortical cataract (ARCC) in the rat.


METHODS
Freshly isolated lenses were stained vitally for DNA with Hoechst 33342. Reactive oxygen species (ROS) and mitochondria were visualized and quantified by dihydrorhodamine 123 (DHR). The fluorescence was quantified using Laser Scanning Confocal Microscopy (LSCM) of vitally stained lenses. Cortical DNA was verified as such by DNAse I digestion. Cataract reflections were determined from digitalized images of light reflections taken with a low magnification light microscope, or with the LSCM.


RESULTS
The anterior surface epithelia of old rat lenses were full of gaps and ragged in appearance with a decrease of over 50% in lens epithelial cell (LEC) density. The surface LECs were frequently seen to have involuted into the cortex at inappropriate sites, forming deposits full of DNA, nuclear and mitochondrial debris, and abundant ROS. These involutions frequently originated near open gaps in the surface epithelia, where they appear to have detached from the capsular membrane. Cortical cataracts in the rat lenses were seen to co-localize with these LEC involutions, as had been seen previously in mice with ARCC.


CONCLUSIONS
ARCC in rats co-localized with inappropriate accumulations of nuclei, mitochondria, DNA, and expression of ROS in debris filled foci. These were the result of both involution of surface LECs into areas of cortical ARCC, and by an extension of the normal bow region deep into the anterior and posterior of cataractous lenses. These results were in complete agreement with our previous studies on ARCC in mice.
Pendergrass
William R
WR
Department of Pathology, University of Washington, School of Medicine, Seattle, WA 98195, USA. pendergr@u.washington.edu
Penn
Phil E
PE
Possin
Daniel E
DE
Wolf
Norman S
NS
D000375:Aging; D000818:Animals; D002386:Cataract / Q000378:metabolism* / Q000473:pathology*; D002452:Cell Count; D002467:Cell Nucleus / Q000648:ultrastructure; D004247:DNA / Q000378:metabolism; D004847:Epithelial Cells / Q000473:pathology; D007904:Lens Cortex, Crystalline / Q000473:pathology; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000648:ultrastructure; D051381:Rats; D011914:Rats, Inbred BN; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012235:Rhodamines
D017382:Reactive Oxygen Species; D012235:Rhodamines; C058319:dihydrorhodamine 123; D004247:DNA