Oxidative Capacity of Atherosclerotic Tissue of Rabbit and Dog, With Special Reference to Succinic Dehydrogenase and Cytochrome Oxidase

Abstract

The oxidative capacity of the succinic oxidase and cytochrome oxidase systems, as measured by the oxidative response to succinate and p-phenylenediamine was studied in slices of aortas from rabbits and dogs subjected to an atherogenic regimen, and in the liver as reference tissue. In both animals, at an early stage in the atherosclerotic process, the oxidative capacity of both systems was increased in the atherosclerotic intima-media layer, separated at the cleavage plane, while at a later stage it was decreased. The intima-media of the uninvolved portions of the aorta showed a decrease in the oxidative capacity of the cytochrome oxidase system, whereas that of the succinic oxidase system remained unchanged. The liver, although the site of massive deposition of lipids, in the rabbit particularly, showed no enzymatic changes at any time during the administration of the atherogenic regimen. These findings indicate that metabolic alterations of the arterial wall are associated with the development of atherosclerosis.