Palinski W, Ord V A, Plump A S, Breslow J L, Steinberg D, Witztum J L
Department of Medicine, University of California San Diego, La Jolla 92093.
Arterioscler Thromb. 1994 Apr;14(4):605-16. doi: 10.1161/01.atv.14.4.605.
Apolipoprotein (apo) E-deficient transgenic mice develop marked hyperlipidemia and progressive atherosclerotic lesions. To explore whether oxidative modification of lipoproteins is involved in atherogenesis in this murine model, we performed extensive immunocytochemical studies. Atherosclerotic lesions ranging from early fatty streaks to very advanced plaques were examined from the aortic valve region and the thoracic and abdominal aorta. Using guinea pig antisera against malondialdehyde (MDA)-lysine and 4-hydroxynonenal-lysine, two epitopes generated during the oxidative modification of low-density lipoprotein (LDL), we demonstrated the presence of these "oxidation-specific epitopes" in atherosclerotic lesions. In early lesions, oxidation-specific epitopes were found predominantly in macrophage-rich areas, whereas diffuse extracellular staining predominated in necrotic areas of advanced lesions. We have previously shown that autoantibodies against MDA-lysine are present in the circulation of humans and rabbits and that the immunoglobulin fraction extracted from their lesions contains autoantibodies against several "oxidation-specific" epitopes. Sera from apoE-deficient mice also contained circulating autoantibodies to MDA-lysine, and both early and advanced lesions were rich in murine immunoglobulins. Titers of serum autoantibodies were significantly higher in apoE-deficient mice than in C57BL/6 mice. Autoantibodies in murine plasma recognized MDA-lysine epitopes in atherosclerotic lesions of rabbits, and the immunostaining was competitively inhibited by excess human MDA-LDL. Similar findings were obtained by competitive radioimmunoassay. Finally, a morphometric technique was developed and tested in these mice that allows a quantitative assessment of aortic atherosclerosis. These findings suggest that in apoE-deficient mice, lipoprotein oxidation is involved in atherogenesis and that these transgenic mice constitute an appropriate model with which to study the antiatherogenic effect of antioxidant intervention.
载脂蛋白（apo）E 缺陷转基因小鼠会出现明显的高脂血症和进行性动脉粥样硬化病变。为了探究脂蛋白的氧化修饰是否参与该小鼠模型的动脉粥样硬化形成过程，我们进行了广泛的免疫细胞化学研究。从主动脉瓣区域以及胸主动脉和腹主动脉检查了从早期脂肪条纹到非常晚期斑块的动脉粥样硬化病变。使用针对丙二醛（MDA）-赖氨酸和 4-羟基壬烯醛-赖氨酸的豚鼠抗血清，这两种表位是在低密度脂蛋白（LDL）氧化修饰过程中产生的，我们证明了这些“氧化特异性表位”在动脉粥样硬化病变中的存在。在早期病变中，氧化特异性表位主要存在于富含巨噬细胞的区域，而在晚期病变的坏死区域则以弥漫性细胞外染色为主。我们之前已经表明，针对 MDA-赖氨酸的自身抗体存在于人和兔子的循环中，并且从它们的病变中提取的免疫球蛋白部分含有针对几种“氧化特异性”表位的自身抗体。载脂蛋白 E 缺陷小鼠的血清中也含有针对 MDA-赖氨酸的循环自身抗体，并且早期和晚期病变中都富含鼠免疫球蛋白。载脂蛋白 E 缺陷小鼠血清自身抗体的滴度显著高于 C57BL/6 小鼠。鼠血浆中的自身抗体识别兔子动脉粥样硬化病变中的 MDA-赖氨酸表位，并且免疫染色被过量的人 MDA-LDL 竞争性抑制。通过竞争性放射免疫测定也获得了类似的结果。最后，开发并在这些小鼠中测试了一种形态计量技术，该技术可以对主动脉粥样硬化进行定量评估。这些发现表明，在载脂蛋白 E 缺陷小鼠中，脂蛋白氧化参与了动脉粥样硬化的形成，并且这些转基因小鼠构成了一个合适的模型，可用于研究抗氧化干预的抗动脉粥样硬化作用。
