A Study of Radiation-Induced Aging: Response of Irradiated and Nonirradiated Mice to Cold Stress

Abstract

Effect of radiation exposure on the life span of animals has been reported by a number of observers (3-5). The mechanism by which life shortening occurs is believed by some investigators to result from the general acceleration of the aging process. Blair (6) theorized that a single exposure of sublethal radiation leaves an irreparable injury, causing premature aging. In chronic exposures, Boche's (5) data suggested that shortening of life span in four species of laboratory animals was proportional to the total dose accumulated. If indeed radiation exposure produces a condition comparable to increased physiologic age, it should be possible to demonstrate it by testing the response of irradiated and nonirradiated animals of the same chronologic age to stress conditions. The above reasoning prompted Curtis and Healy (7) to study the effects of irradiation exposure on ability of mice to withstand typhoid toxin. He reported that mice 12 months after exposure to 525 r of X-rays were less able to withstand this specific toxic stress than were controls. The present study was designed to compare mice naturally aged and mice aged by protracted y-ray exposure in their ability to survive a standard cold stress.