In vivo Laser Confocal Microscopic Findings of Mouse Cornea and Crystalline Lens

Abstract

Purpose:: The purpose of the current study is to investigate in vivo microstructures of anterior segment of normal mouse by in vivo laser confocal microscope (Heidelberg Retina Tomograph2/Rostock Cornea Module (HRT2-RCM)).

Methods:: Twenty-six eyes of 13 mice were analyzed in vivo by HRT2-RCM. For all eyes, confocal microscopic images of the corneal layers and crystalline lens were obtained. Selected images were analyzed qualitatively and cellular densities of the corneal epithelial layers, endothelial cells, and lens epithelial cells were measured.

Results:: Superficial cells were seen as polygonal cell pattern, blight illuminated cytoplasm, reflecting nucleus, and perinuclear dark halo, with a mean cell density of 577±115 cells/mm²(mean±SD). Basal cells had dark cytoplasm without visible nuclei and were closely organized, with a mean cell density of 9312±1777 cells/mm². Sub-basal nerve plexus were observed as numerous fibers which ran in parallel and sometimes connected with anastomoses. Additinally, we could successfully visualized the nerve fiber bundles arranged in a clockwise whorl or vortex pattern in 6 eyes out of 26 eyes. Numerous reflective stellate structures were observed within the anterior and posterior stroma with no clearly visible nuclei. In the anterior stroma, some corneal nerves were observed as hyper-reflective linear structures. The endothelium was seen as hyper-reflective cells with dark limits organized in a honeycomb pattern, with a mean cell density of 2463±292 cells/mm². Additionally, numerous mouse lens fibers as well as Y-shaped lens suture could be visualized clearly in 11 eyes out of 26 eyes. Lens epithelium cells also could be visualized in 7 eyes of 26 eyes; they had dark cell bodies without visible nuclei, bright cell boundaries, and were organized in a regular pattern, with a mean cell density of 4168±636 cells/mm².

Conclusions:: HRT2-RCM can provide high-resolution images of all corneal layers of mice without sacrificing animals or preparing tissue. This new device may be useful for evaluating the mouse cornea during experiment using mouse model. Furthermore, this study demonstrates that HRT2-RCM can visualize in vivo mouse lens and lens epithelium, indicating this device may have a potential to visualize human lens and lens epithelium.

Keywords: microscopy: confocal/tunneling • cornea: basic science • cornea: stroma and keratocytes