Aortic Arteriosclerosis in the Dog After Localized Aortic Irradiation with Electrons

Abstract

The distal segments of the abdominal aortas of 15 dogs were irradiated with electrons in doses ranging from 1,000 to 9,500 rads and were examined histologically at intervals ranging from 2 weeks to 17 months following irradiation. Pronounced aortic arteriosclerosis developed and was sharply localized to the aortic segment irradiated. Except in one dog, radiation-induced arteriosclerosis was more pronounced on the dorsal than on the ventral aortic wall. There was no evidence that severity of aortic arteriosclerosis was related to the dose of irradiation or was increased with time following irradiation. The development of arteriosclerotic lesions of the aorta induced by electron irradiation was similar to that observed after x-irradiation and to that occurring naturally in old dogs. It is suggested that electron irradiation may have caused selective injury of the internal elastic lamina, which was then followed by intimal fibrous proliferation and formation of intimal plaques.