Anatomical study of the corneal structures of three experimental animal models by in vivo Confocal microscopy / 中华实验眼科杂志

ABSTRACT

Background Noninvasive methods such as in vivo confocal microscopy and Orbscan Ⅱ corneal topography have been used to examine ocular surface structure at the cellular level.However,very few domestic reports about the corneal structures of experimental animals investigated by confocal microscopy are available.Objective This study was to compare the anatomical differences of the corneal structures of three frequently used experimental animals presented by in vivo confocal microscopy,and to offer a database on the information provided by the in vivo study of the corneal structures of these animals.Methods Bilateral corneas of 3 clean adult male New Zealand rabbits,3 clean adult male Lewis rats and 3 clean adult male Swiss mice were examined by in vivo confocal microscopy.The morphological characteristics of every layer of the corneas and the endothelial cell densities were analyzed and compared.Results Superficial epithelium cells of the three animal models were characterized as polygon cells with high or low reflective border.The arrangement of the basal epithelial cells was regular with tight contacts but these cells lacked visible nuclei.The Bowman' s layer of cornea presented as an amorphous sheet containing abundant subepithelial plexus.In the rabbits,a highly reflective structure in the corneal stroma wasconfirmed as the nucleus,and the cell density of the posterior stroma was significantly lower than that of anterior stroma(387.5 cells/mm2 versus 223.5 cells/mm2)(U =0.000,P =0.000).Massive light-reflecting astreoids were displayed in the stroma of the rats and the mice.Corneal endothelial cells(CECs)of the three animal models had similar shapes and arrangements,presenting with high refractive cell bodies with dark borders and honeycomb-like arrangements.The CECs densities were 2192.5,1936.0,1565.0 cells/mm2 in the New Zealand rabbits,Lewis rats and Swiss mice,respectively,showing a statistically significant difference among them(H =49.940,P =0.000),and that of the rabbits was significantly higher than that in the rats and mice(x2 =0.000,P =0.000;x2 =0.000,P=0.000).Significant difference was also seen between the rats and the mice in the CECs densities(x2=0.000,P=0.000).Conclusions The CECs of the three animal modes are similar in morphology.But the structures of their stromal cells and endothelial cell densities are different.The combination of in vivo confocal microscopy and Orbscan Ⅱ corneal topography offers high-resolution imaging for each layer of the cornea.