Evaluation of the Relative Pathogenic Roles of Diabetes and Serum Cholesterol Levels in the Development of Cardiovascular Lesions in Rats

Abstract

Previous studies in our laboratory demonstrated that in partially pancreatectomized diabetic rats fed an atherogenic diet containing 5 per cent cholesterol, serum lipid levels rose higher and cardiovascular lesions were more frequent than in nondiabetic rats fed the same diet for three to seven months. This experiment posed the question: Didthe diabetic state per se or the higher levels of cholesterol associated with it account for the greater number of lesions in the diabetic animals? To answer this question, the experiment was repeated, but this time some of the diabetic rats were fed diets with lower amounts of cholesterol than before in order to keep their serum cholesterol levels within the same range as those of the nondiabetic animals (intact or partially pancreatectomized but normoglyceinic) fed the basal atherogenic diet. As before, diabetic rats fed the athero genie diet containing 5 per cent cholesterol developed higher levels of serum cholesterol and more lesions than similarly fed nondiabetics. Other serum lipids were also higher in this group, especially triglycerides and free cholesterol. When serum cholesterol levels in the diabetic animals were not permitted to exceed those in the nondiabetics, the incidence of vascular lesions in the two groups did not differ. The diabetic state per se in this mode, therefore, seemed to play a pathogenic role in atherogenesis by elevating serum lipid levels. Results would indicate that, under theseconditions, at any given level of serum lipid, the diabetic artery is not more susceptible than a nondiabetic artery to this type of atherogenic stimulus.