Sphingosine-1 phosphate prevents ethanol-induced corneal epithelial apoptosis

BACKGROUND: Apoptosis is a programmed cell death in multicellular organisms, found in a wide variety of conditions, including inflammatory process, everywhere in the body, including the cornea and conjunctiva. AIM: To evaluate the effect of a new topical formulation of sphingosine-1 phosphate on preventing apoptosis of the corneal epithelium. SETTING: Medical University. MATERIALS AND METHODS: We tested several formulations suitable for topical application. Twenty-five rabbits were distributed among five groups. Group 1 comprised the controls. In Group 2, 20% ethanol was applied topically for 20 seconds; in Group 3, 50 μM topical sphingosine-1 phosphate was applied 2 hours prior to 20% ethanol application. In Group 4, 200 μM topical sphingosine-1 phosphate was applied 2 hours before the 20% ethanol application. In Group 5, only 200 μM topical sphingosine-1 phosphate was applied. Apoptosis was evaluated using the terminal deoxynucleotidyl transferase biotin-dUTP Nick End Labeling (TUNEL) assay. Pairwise comparisons were performed using t-tests with Scheffe's correction. Data were analyzed using STATA 9.0 statistical software. RESULTS: A suspension of sphingosine-1 phosphate in the presence of Montanox 80 was stable and could be formulated without sonication. Epithelial apoptosis was detected only in Groups 2 and 3. Conclusion: Sphingosine-1 phosphate can prevent ethanol-induced apoptosis in the corneal epithelium of rabbits.