THE EFFECTS OF OXIDATIVE STRESS ON THE EYES OF SPRAGUE–DAWLEY RATS

Abstract

An imbalance between oxidants and antioxidants in favor of the oxidants, potentially leading to damage, is termed as ‘oxidative stress’. Some studies indicate that reactive oxygen species (ROS) may increase in resistance of the aqueous humor drainage or induce the rearrangement of human trabecular meshwork and result in glaucoma finally. An eight-week d-galactose injection was used to mimic high oxidative stress rats. Behavior tests, fundus images, anterior chamber depth, anterior chamber diameter (ACDia) and pupil diameter (PD) were investigated. Intraocular pressure (IOP) measurement and serum were taken for antioxidant capability of superoxide dismutase (SOD) and the amount of nitric oxide (NO). After perfusion, Müller’s cells and astrocyte, microglial and inducible Nitric Oxide Synthase (iNOS) were labeled. The activities of SOD were decreased after induction. The spatial memory ability and muscular endurance were impaired through Morris water maze (MWM) and weight-loaded forced swimming test. These results demonstrated that oxidative stress was exacerbated by d-galactose. The IOP was gradually increased in the third week after d-galactose induction. Immunohistochemical stains showed that the density of Müller’s cells, astrocytes and microglia increased in d-galactose group. Microglia mostly became active. These data indicate that oxidative stress may result in the impairment of behavior, increase of Müller’s cells, astrocyte and microglia which is induced by d-galactose. The correlation between oxidative stress and elevation of IOP should be further studied. These may involve in the pathologies of aging or other neurodegenerative disease.