A esplenectomia aumenta as lesões ateroscleróticas em camundongos deficientes em apoproteína “E” submetidos a uma dieta aterogênica

Abstract

Atherosclerosis is an inflammatory immune disease associated with lipid accumulation in the intima layer of arteries. The spleen plays an important immune function, but its influence in development of atherosclerosis remains unclear. Evaluation of the role of the spleen in atherosclerosis is justified due to the high frequency of total splenectomies and the high prevalence of atherosclerotic disease. In this work, the effect of splenectomy on the development of atherosclerosis in apolipoprotein E (apoE) deficient mice was investigated. ApoE deficient mice were divided into a sham-operated control group (CT) and a splenectomized group (SP). Thirty days after surgery, animals were fed a high fat western diet (with 0.15% cholesterol). After eight weeks, mice were euthanized and their blood, heart, and aorta were subjected to analysis. Total serum cholesterol and anti-oxidized LDL antibodies were measured. Atherosclerotic lesion areas in the aortic root were stained with hematoxylin-eosin and quantified by morfometry. The atherosclerotic lesions in the thoracic and abdominal portions of aorta were determined by assessing the percentage of the luminal surface area stained by Sudan IV. Levels of total serum cholesterol did not vary significantly after splenectomy. Anti-oxidized LDL IgG antibodies were similar between groups. However, compared to the control group, atherosclerotic area in the thoracic and abdominal portions of aorta were significantly increased in splenectomized mice. These data were confirmed by the larger lesions in the aortic root in splenectomized mice. These data indicate that splenectomy increases atherosclerotic lesions in apoE deficient mice fed an atherogenic diet, suggesting a atheroprotector role of the spleen.