Spontaneous corneal dystrophy and generalized basement membrane changes in Fischer-344 rats

Area of Science:

• Ophthalmology
• Pathology
• Toxicology

Background:

• Corneal basement membrane lesions, or corneal dystrophy, are a potential concern in research animals.
• Fischer-344 rats are a common model organism in toxicological studies.

Purpose of the Study:

• To determine the prevalence and severity of corneal basement membrane lesions in Fischer-344 rats.
• To investigate potential correlations between ocular and nonocular basement membrane changes.
• To assess the impact of these lesions on the suitability of rats as biologic test systems.

Main Methods:

• Ophthalmological and histopathological examinations were performed on young, sexually mature Fischer-344 rats (n=25/sex).
• Rats were sourced from multiple commercial breeders.
• Severity of corneal lesions and basement membrane changes in nonocular tissues (renal tubules, vascular internal laminae) were evaluated.

Main Results:

• A high incidence of corneal basement membrane dystrophy was observed across all breeders.
• Rats from one specific breeder exhibited significantly increased lesion severity.
• Advanced corneal lesions were associated with more severe basement membrane changes in renal tubules and vascular internal laminae.

Conclusions:

• Ocular and nonocular dystrophic changes in Fischer-344 rats may share common physiologic or genetic mechanisms.
• The presence of basement membrane lesions did not compromise the animals as biologic test systems.
• Breeder origin is a significant factor influencing the severity of corneal dystrophy in this rat model.