Under normal conditions, antioxidants at the corneal surface are balanced with the production of reactive oxygen species without any toxic effects. Danger from oxidative stress appears when natural antioxidants are overwhelmed leading to antioxidant/prooxidant imbalance. The aim of the present study was to examine the activities of enzymes contributing to the antioxidant/prooxidant balance in normal corneal epithelium of various mammals. The enzyme activities of antioxidant superoxide dismutase and glutathione peroxidase, as well as prooxidant xanthine oxidoreductase/xanthine oxidase were examined using biochemical methods. Results show that superoxide dismutase activity is high in rabbits and guinea pigs, whereas in pigs the activity is low and in cows it is nearly absent. In contrast, glutathione peroxidase activity is high in cows, pigs and rabbits, whereas in guinea pigs the activity is low. As far as prooxidant enzymes are concerned, elevated xanthine oxidoreductase/xanthine oxidase activities were found in rabbits, lower activities in guinea pigs, very low activity in cows and no activity in pigs. In conclusion, the above results demonstrate inter-species variations in activities of enzymes participating in antioxidant/prooxidant balance in the corneal epithelium. It is suggested that the levels of antioxidant and prooxidant enzymes studied in the corneal epithelium might be associated with the diurnal or nocturnal activity of animals. UV rays decompose hydrogen peroxide to damaging hydroxyl radicals and perhaps for this reason large animals with diurnal activity (cow, pig) require more effective peroxide removal (high glutathione peroxidase activity) together with the suppression of peroxide production (low superoxide dismutase activity, low xanthine oxidoreductase activity).

• MeSH
• financování vládou MeSH
• glutathionperoxidasa imunologie   škodlivé účinky   MeSH
• interpretace statistických dat MeSH
• rohovkový epitel fyziologie   chemie   patofyziologie   MeSH
• savci imunologie   MeSH
• superoxiddismutasa imunologie   škodlivé účinky   MeSH
• ultrafialové záření škodlivé účinky   MeSH
• xanthinoxidasa imunologie   škodlivé účinky   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• srovnávací studie MeSH

• MeSH
• finanční podpora výzkumu jako téma MeSH
• imunohistochemie MeSH
• králíci MeSH
• peroxidace lipidů MeSH
• reaktivní formy dusíku biosyntéza   MeSH
• rohovka metabolismus   účinky záření   MeSH
• synthasa oxidu dusnatého metabolismus   MeSH
• tyrosin analogy a deriváty   metabolismus   MeSH
• ultrafialové záření škodlivé účinky   MeSH
• zvířata MeSH
• Check Tag
• králíci MeSH
• zvířata MeSH

• MeSH
• finanční podpora výzkumu jako téma MeSH
• histocytochemie MeSH
• xanthindehydrogenasa analýza   MeSH
• xanthinoxidasa analýza   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• srovnávací studie MeSH