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Abstract
PURPOSE: The authors aimed to establish an in vitro model of the retinal pigment epithelium (RPE) suitable for studies of neural retina-epithelium interactions. METHODS: Sheets of RPE were obtained from Xenopus laevis eyes by Dispase treatment of intact globes. After dispersal in trypsin-EDTA solution, cells were plated onto Matrigel-coated microporous membrane filters and grown in a serum-free defined medium. RESULTS: Confluent cell monolayers obtained after 7 to 10 days of culture appeared by electron microscopy to be morphologically polarized, established junctional complexes, and exhibited transepithelial resistances ranging from 300 to 500 omega.cm2. As did the native epithelium, these cells formed cytoskeletons consisting of circumferential bands of actin myofilaments at their periphery and whorls of cytokeratin intermediate filaments throughout the cytoplasm. Co-culture of freshly isolated neural retinas with monolayers resulted in the apparent reattachment of photoreceptors to the RPE within 3 hours. CONCLUSIONS: Primary cultures of amphibian RPE that express phenotypic characteristics of the epithelium in situ are also capable of establishing adhesive interactions with isolated neural retinas.