Vision Science Program, School of Optometry, Indiana University Bloomington, Indiana, United States.
Department of Biology, Indiana University Bloomington, Indiana, United States.
Invest Ophthalmol Vis Sci. 2024 Apr 1;65(4):18. doi: 10.1167/iovs.65.4.18.
Fuchs endothelial corneal dystrophy (FECD) is a progressive blinding disorder, characterized by increased corneal endothelial excrescences (guttae), corneal endothelial cell loss, and edema. These symptoms are hypothesized to be caused by changes in the extracellular matrix (ECM) and mitochondrial dysfunction in the corneal endothelium. Despite this clinical and biological relevance, a comprehensive animal model that recapitulates all the major disease characteristics is currently unavailable. In this study, we develop such a model to improve our understanding of the signaling pathways involved in the FECD progression and develop strategies for early intervention.
To generate a comprehensive FECD model, we generated a double mutant mouse bearing tamoxifen-inducible knockdown of Slc4a11 and the Col8a2 (Q455K) mutation. We performed optical coherence tomography (OCT) and in vivo confocal microscopy using the Heidelberg Retinal Tomography 3 - Rostock Cornea module (HRT3-RCM) on the mice at 5 weeks of age before tamoxifen feeding to establish baseline values for corneal thickness, endothelial cell density, and test for the presence of guttae. We measured these parameters again post-tamoxifen treatment at 16 weeks of age. We collected corneas at 16 weeks to perform histopathology, immunofluorescence staining for tight junctions, adherens junctions, and oxidative stress. We evaluated endothelial pump function using a lactate assay.
The double mutant tamoxifen-fed animals showed the presence of guttae, and displayed increased corneal thickness and decreased endothelial cell density. Endothelial cells showed altered morphology with disrupted adherens junctions and elevated reactive oxygen species (ROS). Finally, we found that stromal lactate concentrations were elevated in the double mutant mice, indicative of compromised endothelial pump function.
Overall, this mouse model recapitulates all the important phenotypic features associated with FECD.
Fuchs 内皮角膜营养不良（FECD）是一种进行性致盲疾病，其特征为角膜内皮赘生物（guttae）增加、角膜内皮细胞丧失和水肿。这些症状被认为是由角膜内皮细胞外基质（ECM）变化和线粒体功能障碍引起的。尽管具有这种临床和生物学相关性，但目前尚无全面再现所有主要疾病特征的动物模型。在这项研究中，我们开发了这样一种模型，以提高我们对参与 FECD 进展的信号通路的理解，并制定早期干预策略。
为了生成一种全面的 FECD 模型，我们生成了一种双突变小鼠，其携带 tamoxifen 诱导的 Slc4a11 敲低和 Col8a2（Q455K）突变。我们在喂食 tamoxifen 前，使用 Heidelberg Retinal Tomography 3 - Rostock Cornea 模块（HRT3-RCM）对 5 周龄的小鼠进行光学相干断层扫描（OCT）和体内共聚焦显微镜检查，以建立角膜厚度、内皮细胞密度和 guttae 存在的基线值。我们在 16 周龄时再次测量这些参数，然后在喂食 tamoxifen 后测量。我们在 16 周时收集角膜进行组织病理学检查、紧密连接、黏着连接和氧化应激的免疫荧光染色。我们使用乳酸测定法评估内皮泵功能。
双突变型 tamoxifen 喂养的动物表现出 guttae 的存在，并显示出角膜厚度增加和内皮细胞密度降低。内皮细胞形态发生改变，黏着连接中断，活性氧（ROS）水平升高。最后，我们发现双突变小鼠的基质中乳酸浓度升高，表明内皮泵功能受损。
总的来说，这种小鼠模型再现了与 FECD 相关的所有重要表型特征。
