Prevention of cataracts in pink-eyed RCS rats by dark rearing.
Royal College of Surgeons rats have hereditary retinal degeneration and associated posterior subcapsular opacities (PSO) of the lens, detectable by slitlamp at 7-8 postnatal weeks in both pink- and black-eyed rats. The retinal degeneration is intensified by light, especially in pink-eyed rats. A fourth of pink-eyed rats developed mature cataracts by 9-12 months of age, but black-eyed rats whose retinas are protected from light by pigmented irises and pigment epithelium rarely have mature cataracts (3% or less), indicating light may be a factor in cataractogenesis. Prior work had shown that dark rearing reduced the rate of retinal degeneration in pink- but not black-eyed rats, but cataracts were not studied. In the present work, pregnant pink-eyed females were placed in a darkroom 1 week before parturition. Pups were removed over intervals at 20-85 postnatal days for: (a) microscopic study of fresh lenses and of fixed, stained retina and lens, and (b) counts of cells mm-2 of the web-like vitreous cortex after it had been dissected free. The macrophage-like cells are a quantitative index of immune reaction to retinal damage. At 50-53 postnatal days, in pink-eyed cyclic light reared RCS, the mean number of macrophages was 4.6-fold that in congenic controls, but in those that were dark reared it was only 1.4-fold. This was less than the increase in cyclic light reared black-eyed RCS (2.3-fold that in congenic black-eyed controls). Total absence of light reduced retinal degeneration and the number of macrophages, and prevented PSO detectable microscopically.(ABSTRACT TRUNCATED AT 250 WORDS)
O'Keefe
T L
TL
Mount Holyoke College, South Hadley, MA 01075.
Hess
H H
HH
Zigler
J S
JS
Kuwabara
T
T
Knapka
J J
JJ
D000818:Animals; D002386:Cataract / Q000473:pathology / Q000517:prevention & control*; D002452:Cell Count; D003624:Darkness; D004780:Environment, Controlled; D005127:Eye Color / Q000235:genetics*; D007908:Lens, Crystalline / Q000473:pathology; D008264:Macrophages / Q000473:pathology; D051381:Rats; D011922:Rats, Mutant Strains; D012160:Retina / Q000473:pathology; D012162:Retinal Degeneration / Q000235:genetics / Q000473:pathology