Cell-mediated contraction of vitreous explants from chicken embryo: Possibility of screening for therapeutic agents against proliferative vitreoretinal diseases

PURPOSE We aimed to establish a novel screening system for identifying potential therapeutic agents for treating proliferative vitreoretinal diseases (PVDs). In this study, we focused on vitreous explants from chicken embryos and evaluated the usefulness of quantitatively analyzing the effects of potential candidates on cell-mediated vitreous contraction, which leads to blindness in PVDs. METHODS Vitreous explants were extracted from 19-day-old embryonic chickens and then incubated with retinal Müller cells or endothelial cells to permit cell adhesion. After cell adhesion occurred, we examined the effect of the attached cells on the wet weight of vitreous explants as an index of vitreous contraction. We also performed hematoxylin and eosin staining to characterize the cell morphology on the vitreous surface. RESULTS Contraction of the vitreous explants was observed after cell adhesion of not only retinal Müller cells but also endothelial cells. We confirmed the adhesion of these cells on vitreous explants and estimated the number of adherent cells with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) analysis. The cells on the vitreous surface presented an elongated fibroblast-like phenotype. Integrin was found to be a receptor involved in cell adhesion on the vitreous surface. DISCUSSION Our results suggest that vitreous explants from chicken embryos may be novel useful tools for screening antiadhesion therapeutic agents in PVDs. This preliminary study must be validated with human vitreous and human retinal pigment epithelial cells.