Nuclear morphologies of bovine corneal cells as visualized by confocal microscopy

Confocal laser scanning microscopy was used to characterize nuclear morphology of the three cell layers of bovine cornea in vivo. Corneas fixed with formalin were stained with propidium iodide, whereas living cells in nonfixed corneas were stained with PicoGreen. Nuclei in the three corneal cell layers consistently assume strikingly different shapes. Round nuclei were observed throughout the layers of the epithelium of both fixed and living cells. Stromal fibroblasts (keratocytes) showed approximately equal numbers of elliptical and bean-shaped nuclei arrayed in a variety of orientations. Keratocytes near Bowman's layer had almost round nuclei whereas those near Descemet's membrane had more elongated elliptical nuclei. Lobulate nuclei arranged in a regular pattern were observed throughout the endothelium. Some of the lobulate nuclei were large and stained less intensely with the fluorescent dyes. In addition, keratocytes in vitro displayed the same two distinct nuclear morphologies as in vivo. These observations indicate that each cell layer of the cornea contains nuclei with characteristic morphologies and that, in the case of keratocytes, the cells maintain their characteristic nuclear morphologies in vitro.