QUANTITATIVE-ANALYSIS OF IMMUNOGOLD LABELINGS OF COLLAGEN TYPE-I, TYPE-III, TYPE-IV AND TYPE-VI IN HEALTHY AND PATHOLOGICAL HUMAN CORNEAS

Background: We studied the distribution of collagen types I, III, IV a nd VI in one healthy human cornea and in seven pathological human corn eas, in which the disorders were three cases of pseudophakic bullous k eratopathy (two severe, one moderate) and one case each of stage IV ke ratoconus, chronic ulcer, vascularized cornea and disciform keratitis. Methods: Transmission electron microscopy examinations were performed on post-embedding immunogold-labelled sections. The staining was eval uated by gold particle count in the different tissues. The presence or absence of a given antigen was determined by statistical analysis, us ing a d-value test. Results: Our results on healthy corneal tissues co rroborate the data available from previous studies, except for collage n type VI, which we found to be absent in Bowman's layer. In pathologi cal corneas with a collagenous layer posterior to Descemet's membrane, collagen types I, III and especially IV were detected in this collage nous layer. Collagen types I, III and VI were detected in the anterior healed stroma of other pathological corneas, except for the keratocon us cornea, in which intense collagen III staining was observed. Conclu sion: The presence of collagen types I and III in the posterior collag enous layer of our pseudophakic bullous keratopathy corneas suggests t hat this layer corresponds to scar tissue secreted by stimulated endot helial cells.