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Corneal dystrophy in Fischer 344 rats
Abstract:
A spontaneous degenerative lesion of the cornea resembling calcific band keratopathy in man has been observed in 10-15% of the F-344 rats (aged 35-300 days) purchased from a private vendor's closed breeding colony. The lesion appears clinically as punctuate to linear superficial corneal opacities located in the interpalpebral fissure of one or both eyes. Occasional roughening, bleb formation, or pitting of the corneal surface resembling superficial ulcers may be observed. The lesion occurs in both sexes. It is rarely associated with inflammation or irritation. Histologically, it consists of mineral deposits along the epithelial basement membrane and Bowman's space, some of which are large enough to disrupt or destroy portions of the basilar epithelium. Energy dispersive X-ray analysis of the deposits proved them to be composed of calcium and phosphorus. Electron microscopic examination revealed a variety of extracellular laminated and crystalline arrays similar to those seen in humans with band keratopathy. The etiology of the lesion is as yet undetermined. A genetic-associated susceptibility due to hypercalcemia may be involved.
Insights
A spontaneous corneal lesion resembling calcific band keratopathy was found in F-344 rats. This degenerative condition involves mineral deposits and may be linked to genetic susceptibility and hypercalcemia.
Area of Science:
- Ophthalmology
- Veterinary Pathology
- Toxicology
Background:
- A spontaneous degenerative corneal lesion has been identified in F-344 rats.
- This condition clinically resembles calcific band keratopathy observed in humans.
Purpose of the Study:
- To characterize a spontaneous corneal lesion in F-344 rats.
- To investigate the histological and elemental composition of the corneal deposits.
Main Methods:
- Clinical observation of corneal opacities in F-344 rats.
- Histological examination of corneal tissues.
- Energy dispersive X-ray analysis for elemental composition.
- Electron microscopy for ultrastructural analysis.
Main Results:
- The lesion occurred in 10-15% of F-344 rats (35-300 days old).
- Histology revealed mineral deposits in the epithelial basement membrane and Bowman's space.
- Energy dispersive X-ray analysis confirmed calcium and phosphorus composition.
- Electron microscopy showed laminated and crystalline arrays similar to human band keratopathy.
Conclusions:
- The spontaneous corneal lesion in F-344 rats shares characteristics with human band keratopathy.
- Etiology is undetermined, but genetic susceptibility and hypercalcemia are potential factors.
- Further research is needed to elucidate the exact cause and implications of this condition.