Fujihara Masashi, Bartels Emil, Nielsen Lars B, Handa James T
Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA.
Exp Eye Res. 2009 Jun;88(6):1115-23. doi: 10.1016/j.exer.2009.01.017. Epub 2009 Feb 7.
apoB100 lipoprotein particles have been found to accumulate in Bruch membrane prior to the development of age-related macular degeneration (AMD). This work was performed to determine whether mice that overexpress apoB100 in the RPE/choroid and liver develop landmarks of early AMD over time. Mice transgenic for a human genomic fragment encoding the full length human apoB ("apoB100" mice) and litter-mate control mice were given a normal chow or high-fat diet for 12 months. Mice were evaluated for human apoB mRNA expression in the RPE/choroid and liver by RT-qPCR. Phenotypic changes associated with early AMD were evaluated by ultrastructural analysis using transmission electron microscopy. Changes were semi-quantified using linear regression analysis. Both the RPE/choroid and liver of apoB100 mice expressed both human and mouse apoB mRNA. Transmission electron microscopy showed ultrastructural changes consistent with early human AMD including loss of basal infoldings and accumulation of cytoplasmic vacuoles in the RPE, and basal laminar deposits containing long-spacing collagen and heterogeneous debris in Bruch membrane of apoB100 mice. In apoB100 mice given a high-fat diet, basal linear-like deposits were identified in 12-month-old mice. Linear regression analysis showed that the genotype (human apoB transgene) was a stronger influencing factor than high-fat diet in producing AMD-like lesions used in this study. Human apoB100 transgenic mice overexpress apoB in RPE and, with time, develop validated phenotypic changes that are seen in early human AMD. The phenotypic changes were aggravated by feeding a high-fat diet. The apoB100 mouse model could be valuable in determining the role of apoB-containing lipoproteins in triggering the onset of early AMD.
已发现载脂蛋白B100（apoB100）脂蛋白颗粒在年龄相关性黄斑变性（AMD）发生之前就积聚在布鲁赫膜中。开展这项研究是为了确定在视网膜色素上皮（RPE）/脉络膜和肝脏中过表达apoB100的小鼠是否会随着时间的推移出现早期AMD的特征。将编码全长人apoB的人类基因组片段转基因小鼠（“apoB100”小鼠）及其同窝对照小鼠给予正常饲料或高脂饮食12个月。通过逆转录定量聚合酶链反应（RT-qPCR）评估小鼠RPE/脉络膜和肝脏中人类apoB mRNA的表达。使用透射电子显微镜通过超微结构分析评估与早期AMD相关的表型变化。使用线性回归分析对变化进行半定量。apoB100小鼠的RPE/脉络膜和肝脏均表达人类和小鼠的apoB mRNA。透射电子显微镜显示超微结构变化与早期人类AMD一致，包括RPE中基底褶皱的丧失和细胞质空泡的积聚，以及apoB100小鼠布鲁赫膜中含有长间距胶原和异质碎片的基底膜沉积物。在给予高脂饮食的apoB100小鼠中，在12月龄小鼠中发现了基底线性样沉积物。线性回归分析表明，在产生本研究中使用的AMD样病变方面，基因型（人类apoB转基因）比高脂饮食是更强的影响因素。人类apoB100转基因小鼠在RPE中过表达apoB，并且随着时间的推移会出现早期人类AMD中可见的经过验证的表型变化。高脂饮食会加剧表型变化。apoB100小鼠模型在确定含apoB脂蛋白在引发早期AMD发病中的作用方面可能具有重要价值。
