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Eva M Abarca, Rosemary Cuming, Sue Duran, Jayachandra Rapamuran; Development of an ex-vivo trans-corneal permeation model in horses: Epithelial barrier evaluation. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):4164.
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© ARVO (1962-2015); The Authors (2016-present)
Keratomycosis is a major concern in human and veterinary ophthalmology, with horses serving as a natural viable model for human keratomycosis. The aim of this study was firstly to describe an ex-vivo trans-corneal drug permeation model for use in equine corneas, and secondly to present evidence on the integrity of the equine epithelial barrier function for 6 hours.
Fresh equine corneas used in the experiment were obtained from terminal laboratories performed at the J. T. Vaughan Large Animal Teaching Hospital, Auburn University, AL. Corneoscleral buttons (16 mm) were dissected using standard eye bank technique within 2 hours of enucleation. Fluorescent permeation experiments using a Franz diffusion cell method were performed to examine the integrity of the epithelial barrier function during the times studied (2 and 6 hours). Corneas were mounted horizontally between the donor and the receiving compartments of the diffusion cells (exposure window 0.64cm2), which were maintained at 370C. The donor compartment was filled with 1ml of a solution containing 10µM sodium fluorescein. Samples (1ml phosphate buffered saline pH 7.4) were removed from the receiving compartment hourly and replaced with fresh receiving fluid. The fluorescent intensities of the receiving solution samples were analyzed using a spectrofluorometer. Experiments without fluorescein in the donor solution were also performed as negative controls. All the experiments were performed in triplicates. The results were expressed as mean value ±SEM. The differences between values were assessed using a one-way ANOVA (p<0.05).
Fluorescent concentrations detected in the receiving compartment of experiments maintained for 2 and 6 hours were not significantly different than those obtained from the negative control experiment at any time point, showing that the epithelial barrier function was maintained.
This work presented a simple Franz diffusion cell-type modification for use in ex-vivo ocular drug delivery investigations in the equine eye. The results showed that the diffusion cell was able to maintain the integrity of equine epithelial corneal barrier function throughout the 6 hours of the permeation experiment. Investigation into new treatment modalities for horses with keratomycosis may influence development of parallel human therapies and benefit people with this disease.<br />
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