Effects of topical vitamin E on corneal superoxide dismutase, glutathione peroxidase activities and polymorphonuclear leucocyte infiltration after photorefractive keratectomy.
OBJECTIVE
Photorefractive keratectomy (PRK) induces free radical formation and polymorphonuclear (PMN) cell infiltration in the cornea. Vitamin E is a free radical scavenger and protects the cells from reactive oxygen species. We investigated the effects of topical vitamin E on corneal PMN cell infiltration and corneal antioxidant enzyme activities after PRK.


METHODS
We studied four groups, each consisting of seven eyes. Group 1 were control eyes. In group 2 the corneal epithelium was removed by a blunt spatula (epithelial scrape). In group 3, corneal photoablation (59 micro m, 5 dioptres) was performed after epithelial removal (traditional PRK). In group 4 we tested the effects of topical Vitamin E after traditional PRK. Corneal tissues were removed and studied with enzymatic analysis (measurement of corneal superoxide dismutase and glutathione peroxidase activities) and histologically.


RESULTS
Stromal PMN leucocyte counts were significantly higher after mechanical epithelial removal and traditional PRK (p < 0.05). Corneal superoxide dismutase and glutathione peroxidase activities decreased significantly after mechanical epithelial removal and traditional PRK (p < 0.05). In group 4, treated with vitamin E, corneal superoxide dismutase activity did not differ significantly from that in the medically non-treated groups, nor did corneal PMN cell infiltration after traditional PRK. The reduction of corneal glutathione peroxidase activity after PRK was reduced significantly after topical vitamin E treatment.


CONCLUSIONS
Topical vitamin E treatment may be useful for reducing the harmful effects of reactive oxygen radical after epithelial scraping and PRK in that it increases corneal glutathione peroxidase activity.
Bilgihan
Ayse
A
Department of Biochemistry, Gazi University Medical School, Ankara, Turkey. ayseb@med.gazi.edu.tr
Bilgihan
Kamil
K
Yis
Ozgür
O
Sezer
Cem
C
Akyol
Gülen
G
Hasanreisoglu
Berati
B
D000287:Administration, Topical; D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage*; D003315:Cornea / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D005979:Glutathione Peroxidase / Q000378:metabolism*; D054018:Lasers, Excimer; D007958:Leukocyte Count; D020556:Neutrophil Infiltration / Q000187:drug effects*; D009504:Neutrophils / Q000473:pathology; D018903:Photorefractive Keratectomy; D011182:Postoperative Care; D011817:Rabbits; D013482:Superoxide Dismutase / Q000378:metabolism*; D014810:Vitamin E / Q000008:administration & dosage*
D000975:Antioxidants; D014810:Vitamin E; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase