Alteration of Antioxidant system by Aging in Rats

Abstract

Free radicals are the most reactive types of compounds which can cause oxidative damage. They are compounds that contain an unpaired electron. Common examples are the hydroxyl radical, superoxide radical and lipid peroxides. Other reactive agents which can damage the body include singlet oxygen, ozone and oxides of nitrogen.

Free radicals can react very quickly with other compounds to, create new free radicals, therefore setting up a "chain reaction".

Free radicals and other oxygen-derived species are constantly generated in vivo both by chemical accidents or by specific metabolic mechanisms.

The reactivity of various free radicals varies. Some can play a beneficial role as in fighting off infections, however some can cause sever damage to biological molecules, such as, lipids, proteins and DNA. Oxidized protein can lead to cataract formation, oxidized lipid can damage cell membranes and ultimately lead to atherosclerosis, and damaged DNA can lead to mutations and thus to cancer.

Fortunately, cells contain antioxidant defense systems, that can scavenge and minimize the formation of oxygen derived species, and repair systems which deal with molecules that have been oxidatively damaged.