Abstract
Purpose: :
To examine differences between the irradiation of the rabbit cornea with UVB or UVA rays on enzymes participating in the prooxidant/antioxidant balance in the corneal epithelium.
Methods: :
Adult New Zealand white rabbits were employed. Rabbits were divided into four groups. In the first group the corneas were irradiated with UVB (once a day during 5 days, a dose per day 1.01 J/cm2). In the second group the corneas were irradiated with UVA (once a day during 5 days, a dose per day 1.01 J/cm2) and in the third group the corneas were irradiated with UVA (once a day during 5 days, a dose per day 2.02 J/cm2). Afterwards the rabbits were left without any treatment and on day 8 they were sacrificed. Normal eyes served as controls (the fourth group of rabbits). In the scraped corneal epithelium the activities of xanthine oxidoreductase/xanthine oxidase (as prooxidant enzymes) and glutathione peroxidase and superoxide dismutase (as antioxidant enzymes) were investigated biochemically.
Results: :
UVB rays (not UVA rays, even if applied in two times bigger dose) caused dramatical decrease in activities of antioxidant enzymes, whereas the activities of prooxidant enzymes were not decreased.
Conclusions: :
As compared to controls, UVB rays evoked the prooxidant/antioxidant imbalance in the corneal epithelium. After UVA rays the prooxidant/antioxidant balance remained unchanged.
Keywords: cornea: basic science • radiation damage: light/UV • enzymes/enzyme inhibitors