Characterization of Ocular Morphology in Col4a3-/- Mice as a Murine Model for Alport Syndrome.

Abstract

The purpose of this study was to investigate the ocular morphological characteristics of Col4a3-/- mice as a model of Alport syndrome (AS) and the potential pathogenesis. The expression of collagen IV at 8, 12, and 21 weeks of age was evaluated by immunohistochemistry in wild-type (WT) and Col4a3-/- mice. Hematoxylin and eosin (H&E) staining and thickness measurements were performed to assess the thickness of anterior lens capsule and retina. Ultrastructure analysis of corneal epithelial basement membrane, anterior lens capsule, internal limiting membrane (ILM), and retinal pigment epithelium (RPE) basement membrane was performed using transmission electron microscopy. Finally, Müller cell activation was evaluated by glial fibrillary acidic protein (GFAP) expression. Collagen IV was downregulated in the corneal epithelial basement membrane and ILM of Col4a3-/- mice. The hemidesmosomes of Col4a3-/- mice corneal epithelium became flat and less electron-dense than those of the WT group. Compared with those of the WT mice, the anterior lens capsules of Col4a3-/- mice were thinner. Abnormal structure was detected at the ILM Col4a3-/- mice, and the basal folds of the RPE basement membrane in Col4a3-/- mice were thicker and shorter. The retinas of Col4a3-/- mice were thinner than those of WT mice, especially within 1000µm away from the optic nerve. GFAP expression enhanced in each age group of Col4a3-/- mice. Our results suggested that Col4a3-/- mice exhibit ocular anomalies similar to patients with AS. Additionally, Müller cells may be involved in AS retinal anomalies. This animal model could provide an opportunity to understand the underlying mechanisms of AS ocular disorders and to investigate potential new treatments.