Lodovici Maura, Caldini Silvia, Morbidelli Lucia, Akpan Victor, Ziche Marina, Dolara Piero
Department of Pharmacology, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy.
Toxicology. 2009 Jan 8;255(1-2):1-5. doi: 10.1016/j.tox.2008.09.011. Epub 2008 Sep 25.
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.
紫外线诱导的氧化损伤似乎在眼内组织的许多特定病理状况中起主要作用，例如白内障形成和视网膜变性。因此，抗氧化剂和/或清除剂化合物可能保护眼睛免受紫外线诱导的细胞损伤。我们之前报道过，对香豆酸（4-CA）能够保护兔角膜来源的细胞（SIRC）免受紫外线B诱导的氧化损伤。在本研究中，我们评估了4-CA对兔角膜体内紫外线B诱导的细胞损伤的保护作用。使用了12只雄性新西兰白化兔；4只兔子用作对照，一只眼睛滴注赋形剂，对侧眼睛滴注4-CA酸；8只兔子暴露于紫外线B射线（79.2mJ/cm²），并且在紫外线暴露前3天，每只动物一只眼睛每天滴注1滴赋形剂，对侧眼睛每天滴注1滴含4-CA（164ng）的赋形剂。取出角膜和巩膜组织并测量8-氧代-7,8-二氢-2'-脱氧鸟苷（8-氧代dGuo）水平。在房水中测定超氧化物歧化酶（SOD）和黄嘌呤氧化酶（XO）活性。在局部用4-CA处理后，紫外线B诱导的血管高反应性在紫外线B暴露后4小时和24小时强烈降低，8-氧代dGuo水平是氧化DNA损伤的标志物，通过紫外线B照射在巩膜和角膜中显著增加（P<0.05），但是当在紫外线B暴露前3天和暴露后6天每天一次在缓冲溶液中向结膜施用4-CA时，8-氧代dGuo水平与对照相似，并且与紫外线B处理的角膜相比显著降低（P<0.05）。房水中XO活性显著增加。与对照眼相比，在紫外线B照射前3天和照射后6天施用4-CA诱导XO有小但显著（P<0.05）的降低。我们的结果表明，施用4-CA可保护眼组织，从而在低浓度下降低紫外线B辐射的有害作用，可能是通过其自由基清除和抗氧化特性。因此，4-CA可能有助于保护眼睛免受来自阳光、紫外线灯和焊炬的紫外线B暴露后的自由基损伤。
