Hyaluronate distribution in the regenerating retinal pigment epithelium of the rabbit: a study using confocal laser...

The distribution of hyaluronate (HA) in regenerating retinal pigment epithelium (RPE) of the rabbit was examined using immunohistochemistry and confocal laser scanning microscopy. The goal was to determine if there is a correlation between differentiation and HA expression, like that seen in developing tissues, where HA accumulates and then disappears as the tissue matures. In normal RPE cells HA is associated mainly with the apical surface. In regenerating RPE (produced by i.v. injection of sodium iodate to damage the epithelium, regeneration arising from spared cells), HA exhibits a patchy distribution among the more immature cells and is especially prominent where they overlap or pile up on each other. Where cells are more mature and form a compact monolayer of cells, HA is expressed mainly on the apical surface, as in normal RPE. The accumulation of HA among the more immature cells in the regenerating epithelial sheet supports the hypothesis that HA influences differentiation by suppressing cell-cell associations until the proper time for their formation.