Collagen synthesis in lens epithelial cells on capsules containing intraocular lens implants in rabbits: Immunolocalization of prolyl 4-hydroxylase

Background: We evaluated ultrastructurally the presence and distribution of lens epithelial cells and extracellular matrix on the posterior capsule after implantation of a silicone or a polymethylmethacrylate (PMMA) intraocular lens (IOL) in rabbits. The immunolocalization of prolyl 4-hydroxylase, an enzyme involved in procollagen synthesis, was also examined in such cells. Methods: Anesthetized adult albino rabbits (n=12) underwent phacoemulsification and aspiration (PEA) of the crystalline lens and implantation of a silicone or a PMMA IOL into the capsular bag of one eye. They were killed by an intravenous overdose of pentobarbital sodium. The lens capsules were processed for transmission electron microscopy and for immunohistochemical detection of the beta-subunit of prolyl 4-hydroxylase. Results: Ultrastructurally, lens epithelial cells on the posterior capsule evidenced an accumulation of collagenous extracellular matrix. Prolyl 4-hydroxylase immunoreactivity was detected in the cytoplasm of cells distributed on the capsules. Conclusion: Lens epithelial cells are involved in the production of collagenous matrix on lens capsules after PEA and implantation of IOL, resulting in a fibrotic process of the lens capsule.