Low Doses of Ethanol Prevent Oxidative Stress in the Rat Aorta after Exposure to Ionizing Radiation

Abstract

During radiotherapy of tumors, vessels of normal tissues can be in the irradiation zone. It has been shown that in this case, oxidative stress is initiated in the vessels, which subsequently leads to the development of atherosclerosis in them. In this work, the effect of low doses of ethanol on oxidative stress in the aorta of rats after irradiation was investigated. The activity of the angiotensin-converting enzyme in the aortic segments was determined by the hydrolysis of hippuryl-L-histidyl-L-leucine, and the formation of reactive oxygen species was evaluated by the oxidation of dichlorodihydrofluorescein. It has been shown that low doses of ethanol prevent an increase in the activity of angiotensin-converting enzyme and the formation of reactive oxygen species in the aorta of rats after irradiation. The effect depends on the dose of ethanol and the duration of exposure. With acute exposure (administration of ethanol into the mouth), the maximum effect is achieved 3 h before irradiation, and with chronic exposure (self-consumption of ethanol solutions by rats), the optimal dose decreases with increasing consumption time. The optimal dose of ethanol for chronic ethanol consumption (1 week) is 0.49 g /kg per day; it coincides with the dose that reduces the activity of angiotensin-converting enzyme in old animals and in animals treated with NO synthase inhibitor and dexamethasone, as well as with the dose that maximally reduces cardiovascular diseases in humans. The data obtained indicate the possibility of using low doses of ethanol to prevent vascular damage to normal tissues during radiotherapy of tumors.