Measurement of Murine Corneal Epithelial Permeability With a Fluorotron MasterTM Fluorophotometer

Abstract

Abstract: : Purpose: To develop a procedure to measure corneal epithelial permeability in mouse eyes and to use this method to compare corneal permeability in response to experimental dry eye in two different mice strains. Methods: Balb/c and C57BL6 mice, aged 6–8 weeks were treated with subcutaneous injections of 2.5mg/ml scopolamine hydrobromide four times per day and exposed to an air draft and low humidity for up to 12 days. The mice were euthanized, the eyes removed, and the corneal epithelial permeability measured at days 2, 5, and 12. Untreated, day 0, mice were used as controls. After washing the eye three times with 1 ml normal saline, the baseline fluorescence of the eye was measured by placing the eye in a specially fitted cap on the anterior chamber adapter of a Fluorotron Master^TM Ocular Fluorophotometer. The eye was then placed cornea side down in 0.5 microliters of 0.5% sodium fluorescein for 40 seconds. The eye was washed 3 times with 1ml of normal saline from the optic nerve side of the eye. Six measurements of the corneal permeability were then recorded, rotating the eye 60 degrees between each measurement. Results: Experimentally induced dry eye increased corneal epithelial permeability in both mouse strains. The Balb/c mice showed a significant initial increase in permeability at days 2 and 5 with return toward baseline by day 12. In contrast, the C57BL6 mice exhibited a significant increase in permeability at day 2 that was sustained throughout the experiment. Corneal permeability to fluorescein was significantly higher in C57BL6 mice than Balb/c mice at each timepoint, except for day 2. Conclusions: This study describes a method to measure murine corneal epithelial permeability using an ocular fluorophotometer. Experimental dryness increased corneal permeability to fluorescein and strain specific differences were noted.Support: NIH Grant EY11915 (SCP), Allergan, Inc. an unrestricted Grant from Research to Prevent Blindness, the Oshman Foundation and The William Stamps Farish Fund.

Keywords: cornea: epithelium • cornea: basic science