Abstract

P 147

Corneal anatomy of laboratory animals by confocal laser scanning microscopy

Maria Kröger1, Marina Hovakymian1, Oliver Stachs1, Andrea Meyer-Lindenberg2, Ingo Nolte2, Rudolf F. Guthoff1
1Universitäts-Augenklinik Rostock; 2Klinik für Kleintiere, Stiftung Tierärztliche Hochschule Hannover, Hannover

Objective
The present study was designed to study the morphology of living cornea of most frequently used laboratory animals using in vivo laser-scanning microscopy.
Methods
A total of adult 2 dogs, 2 cat, 5 rabbits, 5 rats, 5 mice were included in the present study. The eyes of animals were examined bilaterally with an in vivo confocal laser scanning microscope (Heidelberg Retina Tomograph II/Rostock Cornea Module®, HRTII/RCM).
Results
In all species the corneal epithelium with minimal morphological variations between animal types was visualized. Superficial cells appeared polygonal, with evident nuclei, highly reflective cytoplasm and well-defined cell borders. The intermediate cells had dark cytoplasm and clearly distinguishable bright cell borders, a nucleus could not be observed. The basal cells were smaller and had also dark cytoplasm and bright boundaries.
The Bowman’s layer was absent in dogs and cats. In rabbits, rats and mice the Bowman’s membrane was observed as an amorphous tissue between the epithelial basal cell layer and the anterior stroma.
Subbasal nerve plexus could be visualised in all species. Nevertheless, the morphology of subbasal nerve plexus differed between species in term of the thickness, length and reflectivity of individual nerve fibers.
In dogs, cats and rabbits, the keratocyte nuclei were visualised. In all stromal sections the keratocyte nuclei showed varying sizes, morphology and degrees of reflectivity. A gradually reducing distribution of keratocyte nuclei in anterior-posterior direction could be reproducibly demonstrated in dogs, cats and rabbits.
Interestingly, the appearance of the stroma was in rats and mice different from that observed in dogs, cats and rabbits: here no reflective ovoid nuclei could be visualised. Nevertheless, the stroma was densily populated with numerous reflective interconnected stellate structures.
Stromal nerves were visualized as stretched hyperreflective structures adjacent to keratocytes in all species.
Comparison of confocal images of the endothelial cell layer did not reveal any differences among different animal types: the hexagonal cells with bright cytoplasm and dark boundaries, organized in honeycomb pattern, were visualised in all species.
Conclusions
In conclusion, the cellular patterns of the corneal cell layers of all these five types of animals were relative similar. Nevertheless, some species-specific differences were seen in in vivo confocal imaging.

Copyright: 2009 Porstmann Kongresse GmbH. All rights reserved. Impressum, Disclaimer.