Immunohistochemical detection of betaIG-H3 in scarring human corneas.

Abstract

BetaIG-H3 is a recently described extracellular matrix protein that is present in various organs. In rabbit corneas, increased betaIG (the rabbit form of betaIG-H3) mRNA levels were shown during corneal development and wound healing. In this study, we investigated the localization of betaIG-H3 protein in scarring human corneas. Corneal buttons obtained during keratoplasty were examined. Immunohistological detection using a polyclonal antipeptide antibody against the betaIG-H3 protein was performed on 24 pathological corneas (9 ulcerations, 8 alkali burns, 2 perforating injuries, 5 bullous keratopathy) and 2 normal corneas. In normal corneas, strong staining was present in the basal layer of the epithelium and in the endothelium; the stromal fibers showed faint, uniform immunoreactivity. In all scarring corneas, the epithelium was usually thickened and all of its layers were reactive with the betaIG-H3 antibody. The cytoplasm of the stromal fibroblasts, as well as the stromal fibers around them also showed staining with the antibody. These changes were present in all scarring corneas, irrespective of the pathological process leading to scar formation. These results prove, at the protein level, the presence of increased amounts of betaIG-H3 at the sites of scarring in human corneas.