C57BL/6J-vit/vit mouse model of retinal degeneration: light microscopic analysis and evaluation of rhodopsin levels.
The C57BL/6J-vit/vit mouse is a newly described model of retinal degeneration in which photoreceptor cells die over the course of a year and the retinal pigment epithelium is unevenly pigmented. The present study utilized histological and biochemical techniques to assess the progression of the retinal degeneration in the vit/vit mouse ages 2 weeks to 8 months. Results of systematic morphometric evaluation indicated that the inner nuclear and plexiform layers of the retina are similar in thickness to age-matched C57BL/6J controls, but the outer plexiform layer is significantly thinner by 4 months. Rows of photoreceptor cells are lost at a rate of about one per month beginning at 2 months of age. By 8 months, the photoreceptor cell nuclei have diminished to only two to three rows. Inner segments of the vit/vit retina are similar in length to controls. Outer segments separate from the RPE during the first 2 months, they seem to be elongated at 2-3 months, but become severely disrupted past 4 months. Beginning at about 5 months, numerous darkly-staining cells resembling photoreceptor cell nuclei are observed in the area of the inner and outer segments and the subretinal space. Spectrophotometric analysis of rhodopsin indicated similar levels in vit/vit and controls at 6 weeks but a 50% reduction by 22 weeks. At 46 weeks, the level of rhodopsin in the mutant animal was less than 0.1 nmol per retina. The loss of rhodopsin in the vit/vit retinas correlated strongly with the decreasing number of rows of photoreceptor cells.(ABSTRACT TRUNCATED AT 250 WORDS)
Smith
S B
SB
Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta 30912-2000.
D000375:Aging / Q000502:physiology; D000818:Animals; D004195:Disease Models, Animal; D051379:Mice; D008810:Mice, Inbred C57BL; D010786:Photoreceptor Cells / Q000378:metabolism / Q000473:pathology; D012160:Retina / Q000378:metabolism / Q000473:pathology*; D012162:Retinal Degeneration / Q000378:metabolism / Q000473:pathology*; D012243:Rhodopsin / Q000378:metabolism*; D012374:Rod Cell Outer Segment / Q000473:pathology
D012243:Rhodopsin