Prevention of corneal keratocyte apoptosis after argon fluoride excimer laser irradiation with the free radical scavenger ubiquinone Q10

PURPOSE. To assess in vitro the potential of the free radical scavenger ubi quinone Q10 in preventing keratocyte apoptosis after argon fluoride (ArF) e xcimer laser irradiation. METHODS. Cultured rabbit keratocytes were irradiated at very low single-pul se laser fluences. The cumulative effects generated by three total fluence doses between 12 and 45 mJ/cm(2), representative of single-pulse subablativ e doses during photorefractive keratectomy (PRK) in humans, were evaluated. We employed the following parameters to compare pretreated (10 mu M ubiqui none Q10) and untreated samples: 1) number and morphology of living cells b y Trypan blue test and ultramicroscopy, respectively; 2) level of free-radi cal formation assessed by malonaldehyde quantitation; 3) cellular energy le vel evaluated by ATP assay. RESULTS. Excimer laser irradiation kills cultured keratocytes by inducing a poptosis. The effect increases with the cumulative fluence dose. In the sam ples pretreated with ubiquinone Q10 there were significantly fewer cumulati ve apoptotic events than in the untreated ones. Quantitative analysis of ma lonaldehyde cellular levels suggested this protective action of ubiquinone Q10 was connected with its ability to scavenge laser-generated free radical s. ATP assay also confirmed that it raised cellular energy levels. CONCLUSIONS. The treatment of corneal keratocytes with relatively low conce ntrations of ubiquinone Q10 can prevent apoptosis after ArF excimer laser i rradiation. If these findings are confirmed on human keratocytes this treat ment could be usefully exploited in the PRK surgical procedure. That might lead to a reduction in the occurrence of haze and curvature regression trig gered by programmed cell death.