Age-related changes in the ocular lens of the albino rat: a light and scanning electron microscopic study

ABSTRACT

The eye lens is a minute organ with a complex structure that plays an indispensible role in the process of vision. The study was conducted to detect-age related structural changes that occur in the rat ocular lens and to correlate these changes with the development of senile cataract. Fifteen male albino rats were used in this study. They were divided into three groups young, adult, and aged [1, 6 and 18 months, respectively]. The animals' lenses were removed, dissected, and processed for light and scanning electron microscopy. The width, thickness, and number of lens fibers were assessed using an image analyzer. Statistical analysis of data was carried out using analysis of variance and the Student t-test. In H and E stained sections, the lens of aged rats was seen to be covered by a thick capsule and had a double layer of epithelial cells. The aged lens showed marked disorganization and vacuolation of nuclear fibers. Scanning electron microscopic study revealed irregularities of the lateral borders of the cortical fibers, folding of their surfaces, and few ball and socket interlocking patterns. The nuclear fibers showed microplicae with a decrease in their cross-sectioned areas. Statistical analysis revealed a significant increase in the number and width of the aged nuclear lens fibers and as significant decrease in their thickness, compared with younger ones. Lens fibers undergo some structural changes as a result of aging in the form of irregularities in shape and arrangement, thinning and compaction. These changes could be correlated to age-related optical problems such as senile presbyopia and cataract