Spontaneous Ocular Lesions in Aged Crj: CD (SD) IGS Rats

Abstract

Spontaneous ocular lesions in the 57-and 109-week-old Crj: CD (SD) IGS (IGS) rats (20 males and 20 females at 57 weeks of age, 17 males and 29 females at 109 weeks of age) were investigated histopathologically. At 57 weeks of age, corneal degeneration characterized by focal deposition of basophilic materials in the corneal epithelial basement membrane was observed in both sexes. Preretinal arteriolar loop, retinal dysplasia, and peripheral and diffuse retinal degeneration were detected in the 57-week-old female rats. At 109 weeks of age, corneal degeneration, cataract, and peripheral and diffuse retinal degeneration were observed in male and female rats. The incidences of corneal degeneration in the 109-week-old rats (11.8% in males and 41.4% in females) were significantly lower than those in the 57-week-old rats (50.0% in males and 75.0% in females). In contrast, the incidences of retinal degeneration in the 109-week-old rats (52.9% in males and 75.9% in females) were significantly higher than those in the 57-week-old rats (0% in males and 30.0% in females). It seems that these results contribute to characterize spontaneous ocular lesions in the aged IGS rats.