Spontaneously Occurring Corneal Lesions in 9 Strains of Mice

Abstract

The corneas of nine strains of laboratory mice were histologically examined at 10 and 26 weeks of age. No corneal lesions were detected in any of the ICR or ICR-n/+ mice. There was low incidence of corneal lesions in C57BL/6, BDF₁, and B6C3F₁ mice. Higher incidence of corneal lesions was observed in BALB/cAn, C3H/He, DBA/2, and ICR-n/n mice. The incidence of corneal lesions in both sexes of C3H/He mice and in females of BDF₁, B6C3F₁, BALB/cAn, and C57BL/6 mice was higher at 26 weeks of age than at 10 weeks of age. Corneal lesions in BDF₁, B6C3F₁, BALB/c, C57BL/6, C3H/He, and DBA/2 mice were characterized by deposition of basophilic material in Bowman's membrane, and degeneration of collagen fibers, proliferation of fibroblasts, vascularization, and infiltration of mononuclear cells in the corneal stroma. Corneal lesions of ICR - n/n mice were caracterized by infiltration of neutrophils and mononuclear cells as well as vascularization in the corneal stroma. Thickness of the corneal epithelial layer and number of the epithelial cell rows in all strains of mice decreased at 26 weeks of age compared with those at 10 weeks of age. There were marked differences in thickness of the corneal epithelial layer among different strains of mice at any given age. These results suggest that the development of corneal lesions in mice may be related to genetic factors and aging.