Abstract
In more than half of cases requiring penetrating keratoplasty, the only corneal component of tissue that requires replacement is the endothelial cell layer. For the shortage of donor corneas and the potential of the complication of penetrating keratoplasty, there would be a substantial advantage in being able to replace the endothelial layer alone by autologous transplantation of human corneal endothelium.In this study, biodegradable PDLA、PLGA75:25、PLGA50:50 membranes were prepared as the cell carrier for corneal endothelial transplantation. Biodegradability test, cell viability test and cell seeding efficiency test were conducted to evaluate the clinical application of the lactic acid copolymer on endothelial transplantation. The denudation of corneal endothelium and Descemet’s membrane were conducted to establish the animal disease models.The Results of degradation tests show：The degradation rates of membranes increased with the composition ratio of glycolic acid in membranes；The degradation rates of PLGA50:50 was biggest among all of the three copolymer, met the requirement of the clinical much. At day 25 after the three kinds of polylactic acid copolymer membranes were implanted into rabbit’s anterior chamber, that cornea kept clear without corneal edemas, glaucoma and emergent inflammation implies that all of polylactic acid copolymers adopted in this study were well-biocompatible.Tissue-cultured endothelial cells were with polygonal morphology and well-connected each other; the cell enlarged and the cell density decreased from 1267 ± 46 cells/mm2 to 772 ± 116 cells/mm2 after the first passage. The results of human sclera fibroblast cell viability on copolymer membranes shows there was no negative cell response to the materials. Membrane samples modified with FNC Coating MixR and collagen type I advanced on the seeding efficiency of endothelial cells；however, high concentration of type I collagen may inhibit the plating of corneal endothelial cells. Endothelial cells seeding on concave membranes of PDLA, PLGA75:25, PLGA50:50 modified with FNC Coating MixR distributed densely and the SEM photographs show the seeding endothelial cells concentrated on the center of concave membranes and plated mostly; the TEM investigation shows cell junctions had formed inter-cellularly.The stripping of endothelium and the denudation of Descemet’s membrane were conducted successfully to establish the syndrome of corneal edemas; however, the denudation of Descemet’s membrane brought about trauma, induced retrocorneal membrane which is unfavorable for endothelial transplantation.Above of all，the PLGA50:50 membrane degrades fast and is well-biocompatible, which modified with FNC exhibits good seeding efficiency of corneal endothelial cells and is promising as cell carrier for the corneal endothelial transplantation. The stripping of endothelium induces corneal edemas of animal model successfully. As a result, a elementary system for corneal endothelial transplantation has been set up in this study.