Protection against Superoxide Radicals in Rat Lens

Abstract

Studies have been conducted to determine the mechanisms by which rat ocular tissues may protect themselves against the toxic reactions initiated by superoxide radicals. Such radicals may be formed in the transparent ocular tissues by photochemical as well as metabolic oxidations. A proof of the existence of SOD, the enzyme which dismutates O₂ – to relatively less toxic H₂O₂, has been obtained for the first time in the case of lens and cornea. The activity of the enzyme in lens was lower as compared to that in cornea and retina. The amount of protein giving an activity of one unit varied between 456–600 μg in cornea and 45–92 μg in retina. It is possible that the low activity of SOD in the lens is compensated for by high ascorbate and glutathione. Ascorbate effectively scavenged the superoxide radicals at 10^––6 m. The effectiveness of glutathione was also observed to lie in the same range.