Effect of Aspirin on Experimental Atherosclerosis in Rabbits Submitted to Hypercholesterolemic Diet

Aspirin, besides its antithrombotic activity, has also been quoted for protective effect reducing new coronary lesions. Objective: Considering the growing interest in the study of drugs that prevent the progression of atherosclerotic lesion, the objective of this study was to determine the effect of aspirin in experimental atherogenesis induced in rabbits fed with cholesterol rich diets. Method: Thirty adult, New Zealand white male rabbits, with 3.4 kg of body weight were submitted to a 1.5% cholesterol-rich-diet for 9 weeks. Aspirin was triturated, mixed with chloroform and incorporated to the normal chow. The drug was given to the rabbits every day in portions of 20 g of chow with 100 mg of aspirin. The rabbits were divided in 3 groups as follows: A) Cholesterol-rich-diet (n=10); B) Cholesterol-rich-diet plus aspirin (n=10) and C) Normal chow (n=10). Blood samples were collected before starting the diet, at 5 weeks and at sacrifice (9 weeks) for determination of total cholesterol, triglycerides, enzymes and hematological tests. After sacrifice, staining of the aorta was done by Sudan III for visualization of sudanophillic plaques. The percentual of aorta couvered with lipidic deposits were determined by computerized planimetry. Results: Total cholesterol (mg/dl) was per group: A- TO=52, T5=424 and T9=1.483; B- TO=32, T5=755 and T9=1.436; C- TO=41, T5=22 and T9=27. Planimetry data did not differ among groups A (23.3%) and B (27.3%). Scanning microscopy – the interpretation of the document images in three groups showed insignificant platelet deposition in all aortic segments both in groups B and C. Conclusion: This experiment enhances the theoretic basis for the protective effect of aspirin as an antiaggregant factor in the experimental aortic atherosclerotic lesion.