1120-6721/032-07$03.50/0 R. BRANCATO 1,5 , N. SCHIAVONE 2,5 , S. SIANO 3,5 , A. LAPUCCI 2,5 , L. PAPUCCI 2,5 , M. DONNINI 2,5 , L. FORMIGLI 4,5 , S. ZECCHI ORLANDINI 4,5 , G. CARELLA 1,5 , F. CARONES 1 , S. CAPACCIOLI 2,5 European Journal of Ophthalmology / Vol. 10 no. 1, 2000 / pp. 32-38 Prevention of corneal keratocyte apoptosis after argon fluoride excimer laser irradiation with the free radical scavenger ubiquinone Q10 INTRODUCTION Excimer laser photorefractive keratectomy (PRK) is a safe, effective, and predictable surgical treatment for myopia (1, 2), astigmatism (3) and hyperopia (4). Only a few complications have been reported so far, mainly related to high curvature corrections. The main undesired effect is the formation of a subepithelial scar which can cause significant light scattering; it can be clinically recognized as a stromal haze (5). This PURPOSE. To assess in vitro the potential of the free radical scavenger ubiquinone Q10 in preventing keratocyte apoptosis after argon fluoride (ArF) excimer laser irradiation. METHODS. Cultured rabbit keratocytes were irradiated at very low single-pulse laser fluences. The cumulative effects generated by three total fluence doses between 12 and 45 mJ/cm 2 , representative of single-pulse subablative doses during photorefractive keratectomy (PRK) in humans, were evaluated. We employed the following parameters to compare pretreated (10 μM ubiquinone Q10) and untreated samples: 1) number and morphology of living cells by Trypan blue test and ultramicroscopy, respectively; 2) level of free-radical formation as- sessed by malonaldehyde quantitation; 3) cellular energy level evaluated by ATP assay. RESULTS. Excimer laser irradiation kills cultured keratocytes by inducing apoptosis. The ef- fect increases with the cumulative fluence dose. In the samples pretreated with ubiquinone Q10 there were significantly fewer cumulative apoptotic events than in the untreated ones. Quantitative analysis of malonaldehyde cellular levels suggested this protective action of ubiquinone Q10 was connected with its ability to scavenge laser-generated free radicals. ATP assay also confirmed that it raised cellular energy levels. CONCLUSIONS. The treatment of corneal keratocytes with relatively low concentrations of ubiquinone Q10 can prevent apoptosis after ArF excimer laser irradiation. If these findings are confirmed on human keratocytes this treatment could be usefully exploited in the PRK surgical procedure. That might lead to a reduction in the occurrence of haze and curvature regression triggered by programmed cell death. (Eur J Ophthalmol 2000; 10: 32-8) KEY WORDS: Corneal keratocyte apoptosis, Argon fluoride excimer laser, Ubiquinone Q10, PRK, LASIK Accepted: December 20, 1999 © by Wichtig Editore, 2000 1 Department of Ophthalmology and Visual Sciences, San Raffaele Hospital, University of Milano 2 Department of Experimental Pathology and Oncology, University of Firenze 3 Quantum Electronics Institute, National Research Council, Firenze 4 Department of Anatomy, Histology and Forensic Medicine, University of Firenze 5 Research Group on Apoptosis applied to Ophthalmology, University Hospital San Raffaele, Milano - Italy Brancato 6-03-2000 15:11 Pagina 32