Distribution and Expression of Transforming Growth Factor- β and Platelet-derived Growth Factor in the Normal and Glaucomatous Monkey Optic Nerve Heads

Abstract

Purpose: Remodeling of the extracellular matrix occurs in the lamina cribrosa in progressed glaucomatous optic nerve damage including disc cupping. We examined immunohistochemical changes in the transforming growth factor (TGF)-β and platelet-derived growth factor (PDGF) in the optic nerve head in an experimentally induced glaucoma model. Methods: We used 3 cynomolgus and 2 Japanese monkey eyes. Glaucoma was induced by repeated argon laser photocoagulation of the chamber angle. Eyes were enucleated after disc cupping had formed 3 to 5 months after photocoagulation. The optic nerve head was examined for expression of TGF-β1, -β2 and -β3 and PDGF-A and -B in frozen sections and by the biotin ExtraAvidin-alkali phosphatase method. Results: Normal monkey eyes showed TGF-β1, -β2 and -β3, and PDGF-A and -B in the optic nerve head including the nerve fibers, glial cells, and vascular cells. Glaucomatous eyes showed stronger expression of TGF-β1 and -β2 in the glial cells around the lamina cribrosa. The staining intensities for TGF-β3, PDGF-A and -B were the same as in normal eyes. Conclusions: Eyes with experimental glaucoma showed higher expression of TGF-β1 and -β2 around the lamina cribrosa. These findings may show upregulation of extracellular matrix production as related to remodeling of the lamina cribrosa in glaucoma.