Abstract
Abstract: :
Purpose: Immune recruitment can often lead to greater damage of the cornea than that caused by the initial injury. Using in vitro models, we explored cytokine production following a chemical insult in order to try to assess their validity as an in vitro endpoint for ocular toxicity. Methods: Human corneal and conjunctival cell lines (gifts from Gillette and May Griffith, University of Ottawa) were grown in a fully defined medium and stratified at air-liquid interface. The epithelium was treated for 10-30 min with NaOH (Sigma, Seelze, Germany), sodium dodecyl sulfate (SLS, Merck, Darmstadt, Germany) and TomadolTM 45-7 (Tomadol, Tomah3, Los Angeles, USA) at concentrations expected to cause mild to severe effects. Along with classical in vitro toxicity tests (LDH production and release, hexosaminidase assays and protein assays), cytokine production was measured in the supernatants using the Human Cytometric Bead Array kits (BD Biosciences). The experiments were extended to include tissue recovery. Results: Production of IL-1ß, 6, 8, 10, 12 and TNF-α was detected in the control stratified epithelia. Cytokine production displayed different profiles depending on the toxicant used. One day after exposure to 0.66% NaOH classical tests indicated minimal damage. However a marked increase was detected in both IL-10 and IL-1ß. Cells treated with 0.66% Tomadol lost all cytokine production one day later, though recovery was suggested by standard toxicity tests. Exposure to SLS resulted in a transient increase in TNF-α, IL-6, 8 and 10, a decrease in IL-12 but no change in IL-1ß. Conclusions: Cytokine production could be a sensitive marker of epithelial damage. Our results indicate that this pattern might be sensitive to the type of toxicant. Cytokines can be measured non-invasively in human tears, offering the potential of assessing toxic effects in splash injuries.
Keywords: ocular irritancy/toxicity testing • cytokines/chemokines • wound healing