title: The reversibility of UV-B induced alterations in optical properties of the rabbit cornea depends on dose of UV irradiation.
abstract: Solar UVB radiation evokes photokeratitis, accompanied by increased corneal hydration and changes in corneal transparency, resulting in increased light absorption. Corneal optical properties are disturbed and visual acuity decreased. The aim of this study was to investigate the reversibility of these UVB-induced changes. Rabbit corneas were irradiated with UVB doses of 0.5 J cm(-2) or 1.01 J cm(-2) during 4 days. Some rabbits were sacrificed after the last irradiation and some 2 months later. Corneas were investigated spectrophotometrically for light absorption, and corneal hydration was evaluated by central corneal thickness with an ultrasonic pachymeter. Corneal impression cytologies were examined immunohistochemically for proinflammatory cytokines and malondialdehyde. The increased corneal light absorption, hydration and the staining of immunohistochemical markers found in corneas after irradiation returned to normal values during 2 months in corneas irradiated with the lower UVB dose. In contrast, in corneas irradiated with the higher UVB dose, a moderate but statistically significant increase in corneal light absorption, hydration and positive immunohistochemical stainings remained as residual changes. This was in contrast to normal corneas, where the staining of proinflammatory cytokines as well as malondialdehyde was negative. In conclusion, the reversibility of UVB-induced disturbances was dependent on UVB dose.
authors.affiliation: Laboratory of Eye Histochemistry and Pharmacology, Institute of Experimental Medicine, Center of Excellence, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: Cestmir
authors.initials: C
authors.lastname: Cejka
authors.forename: Josef
authors.initials: J
authors.lastname: Rosina
authors.forename: Jakub
authors.initials: J
authors.lastname: Sirc
authors.forename: Jiri
authors.initials: J
authors.lastname: Michalek
authors.forename: Blanka
authors.initials: B
authors.lastname: Brunova
authors.forename: Jitka
authors.initials: J
authors.lastname: Cejkova
mesh_terms: D000818:Animals; D003315:Cornea / Q000378:metabolism; D065306:Corneal Injuries; D063171:Corneal Pachymetry; D016207:Cytokines / Q000096:biosynthesis; D004307:Dose-Response Relationship, Radiation; D007634:Keratitis / Q000209:etiology / Q000378:metabolism / Q000473:pathology*; D015227:Lipid Peroxidation; D008315:Malondialdehyde / Q000378:metabolism; D018384:Oxidative Stress; D011817:Rabbits; D011829:Radiation Dosage; D011833:Radiation Injuries, Experimental; D020127:Recovery of Function / Q000502:physiology / Q000528:radiation effects*; D014466:Ultraviolet Rays / Q000009:adverse effects*; D014867:Water / Q000378:metabolism
chemical_list: D016207:Cytokines; D014867:Water; D008315:Malondialdehyde