The effect of oxidative stress on inbred mice of different ages.

The effect of oxidative stress applied for 2 months was compared in adult (14-month-old) and aged (27-month-old) female BALB/c mice. The stress was administered in two ways. One group of animals received a high dose of H2O2 (0.5% H2O2 in drinking water) the other one was given a low dose of H2O2 (0.4 ml of 0.5% H2O2 by esophageal cannula every alternate day). After a 2-month treatment the activity of superoxide dismutase (SOD), catalase and lipid peroxidation capacity were measured in liver homogenates of mice. The activity of catalase and capacity of lipid peroxidation gradually decreased as a function of age while the SOD activity did not reduce even in older mice. The aged-mice could tolerate a high dose of H2O2 mainly by increasing SOD activity. As a result of intake of low dose of H2O2 in old animals SOD activity was decreased and lipid peroxidation capacity was getting higher suggesting that in this life period the liver tissue is very sensitive to chronic, oxidative stress effects of low dose.