Loss of trans-epithelial impermeability of a confluent monolayer of Madin-Darby canine kidney (MDCK) cells as a determinant of ocular irritancy potential

By Shaw, A.J. - Clothier, R.H. - Balls, M.

The short-term exposure of a confluent layer of MDCK cells to a series of test agents of varying ocular irritancy potential demonstrated that the tight junctions between these cells were affected in such a way that fluorescein could leak through in a dose-related manner. Rankings of test agents in order of potency to promote "fluorescein leakage" correlated well with neutral red release results (r = 0.98) and ranked toxicity closely with in vivo eye irritancy data. However, the neutral red release assay produced negative results for three inorganic irritants, whereas these were detected using the fluorescein leakage assay.