Aortic Intimai Lesions and Serum Lipids in Wild Baboons

Abstract

Due to the sparsity of information on blood lipid values and naturally occurring arterial lesions in wild baboons, 77 newly captured baboons (Papio ursinus orientali!) of both sexes were examined. The body weights, used as indicators of age, ranged from 1.3 to 35.9 kg. Within 24 h after capture, venous blood samples for determination of blood lipid values were obtained prior to euthanasia. Autopsies were conducted immediately and the aortas, with the iliac arteries attached, were fixed prior to gross staining with Sudan IV for determination of intimai sudanophilia, while representative blocks of aortic tissues were examined histologically. All intimas exhibited some degree of fatty streaking and approximately 63% of the aortas contained fibromuscular intimai plaques. During the immediate postnatal period, the serum cholesterol levels of the neonate rose sharply from the average birth level of ±75 to ±224 mg%. A gradual decrease in serum cholesterol levels then accompanied the increase in body weight (age) after weaning until the average adult value of 85 mg% was attained in juveniles of 15 kg body weight. No correlation was found between serum cholesterol, triglycerides, total fatty acids, aortic intimai sudanophilia and body weight, but the indications are that a relationship may exist between body weight and severity of aortic intimai hyperplasia. Male baboons weighing between 10 and 15 kg and females weighing between 6 and 10 kg are considered to be the most suitable animal models for experimental atherosclerosis research.