Advancing the treatment of conjunctival scarring: a novel ex vivo model.

OBJECTIVES To develop and validate a novel ex vivo model of conjunctival contraction. METHODS Ex vivo segments of conjunctiva were maintained in culture for 4 weeks in permeable support plates. Digital images were obtained twice a week to monitor contraction using tissue area changes and weekly weight measurements. Investigated were the effects of known contraction stimulators (fetal bovine serum and transforming growth factor β(2)) and of the matrix metalloproteinase inhibitor GM6001. Microscopic contraction, tissue organization, and cell viability (using the cell vital dye carboxyfluorescein diacetate) were monitored by confocal reflection and 2-photon microscopy, revealing detailed real-time kinetics of tissue remodeling. RESULTS Fetal bovine serum and transforming growth factor β(2) induced significant tissue contraction in conjunctiva segments, with no changes in cell viability. This correlated with dramatic and specific degradation of the collagen component in the tissue. Contraction and collagen degradation were reduced in the presence of GM6001. CONCLUSIONS Ex vivo segments of conjunctiva can be used as an integral model system to provide a higher level of understanding about the efficacy of antiscarring therapies and can help bridge the current gap between in vitro and in vivo models. CLINICAL RELEVANCE Scarring leads to the failure of several ocular surgical procedures. This novel ex vivo model recapitulates tissue contraction (with kinetics close to that of in vivo scarring) and allows for a more physiological analysis of conjunctival scarring, which could better evaluate potential therapeutic targets.