Lewis J C, Taylor R G
Department of Pathology, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, North Carolina 27157.
Histochem J. 1994 Nov;26(11):833-43. doi: 10.1007/BF00162928.
Ultrastructural autoradiography has been used to test the hypothesis that atherosclerotic regions of vessels differ with respect to lipoprotein uptake and localization. White Carneau pigeons, in which the prevalence and localization of aortic lesions are highly predictable, were fed a 0.25% cholesterol-supplemented diet to accelerate atherosclerosis. One hour prior to necropsy the birds were given a single intravenous injection of homologous [125I]LDL (low-density lipoprotein). Plasma die-away and tissue distribution of label were determined, and after the birds had been killed, the aortas, spleen and liver were processed for electron microscope autoradiography. Initial [125I]LDL uptake was rapid, with 35% of the label removed within 30 min. Predominant accumulation was in the liver, followed by the lung, kidney, the spleen and the aorta, in which the [125I]LDL level was approximately 4% that of the liver. Autoradiographic analysis documented hepatocyte (33%) and Kupffer cell (19.9%) localization in the liver and reticuloendothelial cell (57.4%) localization in the spleen. The aortic analysis involved serially sectioned lesions for direct comparison of non-lesion, lesion/non-lesion interface (edge) and deep lesion regions. Analysis of 2275 silver grains documented a ten-fold increase in LDL accumulation at the lesion edge (as compared to adjacent non-lesion) where macrophage foam cells contained more than 70% of the label. The other 30% was distributed equally among endothelium, the intimal matrix and smooth muscle cells. This distribution changed with more complex (deeper) lesions, although grain density in the complex lesions was comparable to the edge. In the complex regions, macrophage foam cell grains were reduced to 37%, whereas smooth muscle cell (22%) and the extracellular matrix (24%) label were both increased. These studies substantiate enhanced accumulation of lipoprotein specifically at lesion sites in the aorta and demonstrate a shift from macrophage localization at the developing edge to smooth muscle cell and the extracellular matrix in more complex deeper lesions.
超微结构放射自显影术已被用于检验血管粥样硬化区域在脂蛋白摄取和定位方面存在差异这一假说。白卡诺鸽主动脉病变的发生率和定位具有高度可预测性，给它们喂食添加了0.25%胆固醇的饲料以加速动脉粥样硬化。在尸检前1小时，给这些鸽子单次静脉注射同源的[125I]低密度脂蛋白（LDL）。测定血浆放射性消失情况和标记物的组织分布，鸽子处死后，对主动脉、脾脏和肝脏进行电子显微镜放射自显影处理。最初[125I]LDL的摄取很快，30分钟内35%的标记物被清除。主要蓄积部位是肝脏，其次是肺、肾、脾脏和主动脉，主动脉中[125I]LDL水平约为肝脏的4%。放射自显影分析表明，肝脏中肝细胞（33%）和库普弗细胞（19.9%）有标记物定位，脾脏中网状内皮细胞（57.4%）有标记物定位。对主动脉的分析包括对病变进行连续切片，以便直接比较非病变区域、病变/非病变界面（边缘）和深部病变区域。对2275个银颗粒的分析表明，病变边缘的LDL蓄积增加了10倍（与相邻的非病变区域相比），其中巨噬细胞泡沫细胞含有超过70%的标记物。其余30%平均分布在内皮细胞、内膜基质和平滑肌细胞中。随着病变变得更复杂（更深），这种分布发生了变化，尽管复杂病变中的颗粒密度与边缘处相当。在复杂区域，巨噬细胞泡沫细胞颗粒减少到37%，而平滑肌细胞（22%）和细胞外基质（24%）的标记物都增加了。这些研究证实了脂蛋白在主动脉病变部位的蓄积增强，并表明在更复杂的深部病变中，标记物从病变边缘的巨噬细胞定位转移到了平滑肌细胞和细胞外基质。
