Swelling evaluation of "Scyliorhinus Canicula L." cornea.

The cornea of "Scyliorhinus Canicula L.," and Elasmobranch fish species, is generally considered to be a nonedematic tissue. We reinvestigated swelling capacities of these corneas by determining ultrastructural morphological parameters such as diameters, interfibrillar distances, and number of fibers per surface following several immersions of 25 micron sections of stroma in 0.15 M NaCl solution. Absorbed solution in corneal extracellular matrix induced changes in the above-mentioned morphological parameters. The generated changes are more important in Scyliorhinus Canicula L. than in mammalian stromas that have been studied. Elasmobranch corneas, however, remain transparent because new morphological parameters of the swelled tissue are still compatible with physical requirements of light transmission. Swelling impact on mammalian corneas, although weaker, generates morphological parameters that will diffuse light and diminish tissue transparency. Sutural fibers, the most original anatomical Elasmobranch species characteristic, are supposed to serve as mechanical binding of collagen network fibers. We observed that sutural fibers do swell by themselves and could additionally canalize solutions in stroma.