Protective effect of 4-coumaric acid from UVB ray damage in the rabbit eye.
UV-induced oxidation damage seems to play a major role in a number of specific pathological conditions of intraocular tissues, such as cataract formation and retinal degeneration. Therefore, antioxidant and/or scavenger compounds might protect the eyes from UV-induced cellular damage. We previously reported that 4-coumaric acid (4-CA) is able to protect rabbit corneal-derived cells (SIRC) from UVB-induced oxidation damage. In this study we evaluated the protective effect of 4-CA against UVB-induced cell damage in rabbit cornea in vivo. Twelve male New Zealand albino rabbits were used; four rabbits were used as a control and received vehicle in one eye and 4-CA acid in the contralateral eye; eight rabbits were exposed to UVB rays (79.2mJ/cm(2)) and three days before to UV exposure each animal received 1 drop/day of vehicle in one eye and 1 drop/day of vehicle containing 4-CA (164ng) in the contralateral eye. Corneal and sclera tissues were removed and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) levels were measured. Superoxide dismutase (SOD) and xanthine oxidase (XO) activities were determined in aqueous humour. UVB-induced vessel hyper-reactivity was strongly reduced at 4 and 24h after UVB exposure after local treatment with 4-CA, 8-oxodGuo levels, a marker of oxidative DNA damage, were significantly increased (P<0.05) in sclera and cornea by UVB irradiation, but when 4-CA was administered to the conjunctiva in a buffered solution once a day for 3d before and 6d after UVB exposure, levels of 8-oxodGuo were similar to controls and significantly reduced (P<0.05) compared to UVB-treated corneas. XO activity in the aqueous humour was significantly increased. The administration of 4-CA for 3d before and 6d after UVB irradiation induced a small but significant (P<0.05) reduction of XO compared with control eyes. Our results indicate that the administration of 4-CA protects eye tissues, thus reducing the harmful effect of UVB radiation at low concentration, probably through its free radical scavenging and antioxidant properties. Therefore, 4-CA may be useful in protecting the eye from free radical damage following UVB exposure from sunlight, UV lamps and welding torches.
Lodovici
Maura
M
Department of Pharmacology, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy. maura.lodovici@unifi.it
Caldini
Silvia
S
Morbidelli
Lucia
L
Akpan
Victor
V
Ziche
Marina
M
Dolara
Piero
P
D000080242:8-Hydroxy-2'-Deoxyguanosine; D000818:Animals; D001082:Aqueous Humor / Q000201:enzymology / Q000378:metabolism / Q000528:radiation effects; D003315:Cornea / Q000201:enzymology / Q000378:metabolism / Q000528:radiation effects; D003373:Coumaric Acids / Q000494:pharmacology*; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000378:metabolism; D005123:Eye / Q000201:enzymology / Q000378:metabolism / Q000528:radiation effects*; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects; D011422:Propionates; D011817:Rabbits; D011837:Radiation-Protective Agents; D012590:Sclera / Q000201:enzymology / Q000378:metabolism / Q000528:radiation effects; D013482:Superoxide Dismutase / Q000378:metabolism; D014466:Ultraviolet Rays / Q000009:adverse effects*; D014969:Xanthine Oxidase / Q000378:metabolism
D003373:Coumaric Acids; D011422:Propionates; D011837:Radiation-Protective Agents; D000080242:8-Hydroxy-2'-Deoxyguanosine; D013482:Superoxide Dismutase; D014969:Xanthine Oxidase; D003849:Deoxyguanosine; C495469:p-coumaric acid