Morphological changes in the anterior segment of the Abyssinian cat eye with hereditary rod-cone degeneration.

PURPOSE

The purpose of this study was to investigate morphological changes of the anterior segment of the eye in Abyssinian cats with progressive rod-cone degeneration and to correlate them with blood flow data obtained in the same animals.

METHODS

Sections of the left eyes of six normal cats and of eight cats with different stages of hereditary retinal degeneration were prepared for transmission and scanning electron microscopy. Tangential and sagittal sections were also stained with antibodies against substance P, tyrosine hydroxylase, panneuronal marker PGP9.5, nitric oxide synthase, synaptophysin, and smooth muscle alpha-actin.

RESULTS

In Abyssinian cats with hereditary rod-cone degeneration, significant changes were observed in the iris consisting of irregularities in the vascular wall of smaller arteries without changes in their innervation pattern. The ciliary processes were shorter than in normal cats, and their structure appeared more compact and retracted. Slight changes were also observed in the anterior part of the ciliary epithelium. The anterior chamber angle region did not appear to be affected.

CONCLUSIONS

Clear morphological correlations to the physiological blood flow data were observed in the anterior eye segment, pointing not only to functional but also morphological vascular abnormalities in this animal model for retinitis pigmentosa.