Prevention of corneal keratocyte apoptosis after argon fluoride excimer laser irradiation with the free radical scavenger ubiquinone Q10.
OBJECTIVE
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/cm2, representative of single-pulse subablative doses during photorefractive keratectomy (PRK) in humans, were evaluated. We employed the following parameters to compare pretreated (10 microM 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 assessed by malonaldehyde quantitation; 3) cellular energy level evaluated by ATP assay.


RESULTS
Excimer laser irradiation kills cultured keratocytes by inducing apoptosis. The effect 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.
Brancato
R
R
Department of Ophthalmology and Visual Sciences, San Raffaele Hospital, University of Milano, Italy. brancato.rosario@hsr.it
Schiavone
N
N
Siano
S
S
Lapucci
A
A
Papucci
L
L
Donnini
M
M
Formigli
L
L
Orlandini
S Z
SZ
Carella
G
G
Carones
F
F
Capaccioli
S
S
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000528:radiation effects; D002452:Cell Count; D002478:Cells, Cultured; D003067:Coenzymes; D003315:Cornea / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D019610:Cytoprotection / Q000187:drug effects* / Q000528:radiation effects; D005347:Fibroblasts / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D016166:Free Radical Scavengers / Q000494:pharmacology*; D007834:Lasers / Q000009:adverse effects*; D008315:Malondialdehyde / Q000378:metabolism; D011817:Rabbits; D014451:Ubiquinone / Q000031:analogs & derivatives* / Q000494:pharmacology
D003067:Coenzymes; D016166:Free Radical Scavengers; D014451:Ubiquinone; D008315:Malondialdehyde; D000255:Adenosine Triphosphate; C024989:coenzyme Q10