Role of fibronectin in closure of YAG trabeculopuncture

The distribution of fibronectin during the healing process following Neodymium-YAG laser trabeculopuncture was studied in six live normal monkeys' eyes. Unfixed frozen sections were analyzed for distribution of fibronectin in the lasered and non-lasered sites one hour, 18 hours, eight days and ten weeks after treatment, by utilizing immunofluorescent staining of rhodamine-conjugated goat anti-serum against human fibronectin. Two eyes were not treated and served as controls. Control eyes and non-lasered sections from all laser treated eyes demonstrated a faint distribution of fibronectin along the trabecular beams, with a more prominent staining in the inner and outer walls of Schlemm's canal. Fibronectin, probably derived from plasma, was present one hour after treatment at the fibrin clot and along the walls of the crater formed by laser impact. However, 18 hours and eight days after treatment, an abundance of fibronectin, was evident along the crater's surface suggesting local production by trabecular cells. Ten weeks after laser injury, when scar formation was already complete, fibronectin could hardly be detected. We propose that the production and deposition of fibronecting may play a role in trabecular meshwork repair and may help to account for the spontaneous closure of laser trabeculopunctures.