Age-Associated Changes in the Cornea, Lens and Retina of the Albino Rat Eye: A Histological and Immuno-Histochemical Study

Abstract

Background: Age-related changes occur throughout the body including vision. Aging has various effects on the visual system affecting both external and internal portions of the eye. Age-related visual deterioration may be due to both neural and optical factors. Aim of the Work: To study the normal histological changes of aging on the cornea, lens and retina of albino rat eye. Materials and Methods: In this study twenty-four male albino rats were used. They were divided into Two groups: Group (1) young-aged group (3-6 months) and Group (2) old-aged Group (22-26 months). All animals were sacrificed and their eye balls were extracted and prepared for light microscopic examination. Immuno-histochemical stain was also added to detect apoptosis. Results: It was revealed that aging induced various histological changes in the eye of albino rat. The cornea showed irregular surface with atrophy of the epithelial cells and wide separation of corneal lamellae with loss of keratocytes. The lens subcapsular epithelial cells appeared few and disarranged. The cortical lens fibers lost their nuclei. The retina showed diminished retinal thickness, damage of some ganglion cells and retinal pigmented epithelial cells. The outer nuclear layer revealed marked diminution of its thickness with small dark nuclei. Rods and cones showed decreased density. The Bruch's membrane appeared illdefined and irregular with some adherent deposits and blood leakage in the choriocapillaries. The immunohistochemical stain revealed appearance of some apoptotic cells in the cornea, lens subcapsular epithelial cells and ganglion cell layer as well as pigment epithelial cells of the retina in old-aged rats. Conclusion:Normal aging is associated with some histological and immuno-histochemical changes that could explain the visual impairment observed in elderly