DEPOSITION OF EXTRACELLULAR-MATRIX ON INTRAOCULAR LENSES IN RABBITS -AN IMMUNOHISTOCHEMICAL AND TRANSMISSION ELECTRON-MICROSCOPIC STUDY

Background: We examined by transmission electron microscopy the accumu lation of extracellular matrix on intraocular lenses (IOLs) implanted experimentally into rabbit eyes, and evaluated the immunolocalization of such extracellular matrix components as collagen types I, III, and IV, and cellular fibronectin on these IOLs. Methods: Phacoemulsificati on and aspiration of the crystalline lens were performed and an IOL wa s implanted into the capsular bag of each eye of each of 16 adult albi no rabbits under general anesthesia. After up to 12 weeks, the animals were killed and the IOLs were removed. Specimens were processed for t ransmission electron microscopy or for immunohistochemical detection c ollagen types I, III, and IV, and cellular fibronectin. Results: Trans mission electron microscopy revealed an accumulation of extracellular matrix between the residual anterior lens capsule and the surface of a n IOL explanted 4 weeks after surgery. Collagen types I and III and ce llular fibronectin were detected immunohistochemically on each IOL in association with cellular deposits. Type IV collagen-immunoreactive ma trix was not seen on the optic portion, but was detected on the haptic portion of one of six IOLs examined. Conclusion: Each component of th e extracellular matrix that is deposited on the IOL supplies scaffoldi ng for the adhesion and proliferation of cells, These components are c onsidered to be produced by cells such as lens epithelial cells and ma crophages that adhere to the IOL surface.