Increased platelet aggregability following an atherogenic diet in rabbits

In atherosclerosis researches different animal models are used but the most common is the rabbit, because of the easy development of atherosclerotic lesions. Atherosclerosis is a multicellular process and platelets play an important role in atherogenesis. Excessive plasma lipids stimulate platelet aggregability and thus atherosclerosis development. The effects of an atherogenic diet on lipid status, abdominal aorta wall structure, and platelet aggregability were studied in rabbits. Adult male Chinchilla rabbits were fed an atherogenic diet (2% edible oil solution of crystaline cholesterol at 8 mg cholesterol per kg b.wt.daily) for 8 weeks. Plasma lipid levels (triglycerides, total cholesterol, LDL-cholesterol, HDL-cholesterol, and LDL/HDL ratio) and platelet aggregability were then measured and compared to the values obtained for control animals. Histological analysis showed atherogenic changes in the abdominal aorta wall of the experimental animals. Total plasma cholesterol level, plasma LDL-cholesterol, and LDL/HDL ratio were significantly increased compared to the controls (p <0.01), as well as triglyceride and HDL-cholesterol levels (p <0.05). Platelet aggregability was also significantly increased (p <0.01) after the atherogenic diet in comparison with controls when ADP, at concentrations both of 5 and 10 mumol/L, was used as the aggregant. Disaggregation was common in control animals but this phenomenon was not recorded in the experimental animals. It can be concluded that an 8-week atherogenic diet in rabbits induced marked changes of the lipid parameters, provoked atherogenic changes in the abdominal aorta wall and increased platelet aggregability.