Abstract
Purpose :
The keratoconjunctiva of the ocular surface is directly irradiated with solar ultraviolet light (UV) and exposed to many stresses compared with organ tissue. Accordingly, various UV-induced diseases affecting keratoconjunctiva, such as cataracts and photokeratitis have been based on epidemiological data. The production of reactive oxygen species (ROS) and the mitogen-activated protein kinase (MAPK) signaling cascades have been speculated as one of the mechanisms of UV-induced cytotoxicity.
Recently, it have reported that the tea catechin ,especially, (-)-Epigallocatechin Gallate (EGCG) and (-)-Epigallocatechin 3-(3”-O-Methyl) Gallate (EGCG 3"Me) have numerous bioactivity, for example, anti-allergy, anti-oxidant, anti-inflammation, and anticancer activity. Furthermore, recent study showed that treatment with EGCG prevented the increment of apoptotic cells in dry eye corneas. To elucidate the protective effects of catechin on the UV-induced cytotoxicity in cultured human corneal epithelium (HCE-T) cells, we determined utilizing we examined a role of MAPK in protective effects of EGCG and EGCG 3"M on UV-induced cytotoxicity in the HCE-T cells.
Methods :
We cultivated HCE-T (the SV40-immnortalized human corneal epithelial cell line; RCB No.2280) cells in (DMEM:HamF12=1:1)+ 5%FBS+ 5mg/ml Insulin+ 10ng/ml Human epidermal growth factor+ 0.5%DMSO+ 1%penicillin streptomycin in 5% CO2, 37 celsius environment. HCE-T irradiated UV (312nm, 4.94 mW/cm2, 296 mJ/cm2). HCE-T cells were treated with catechins for 1 hr before UV radiation. After UV exposure, the production of reactive oxygen species (ROS), apoptotic rate and mitogen-activated protein kinase (MAPK) activity were determined.
Results :
The increment of ROS production, apoptotic cells, and MAPK activity by UV exposure was prevented by treatment with catechins. These EGCG-mediated cellular events were effectively blocked by MAPK inhibitors.
Conclusions :
These results suggest that EGCG might attenuate UV-induced cytotoxicity through the inhibition of the MAPK-signaling. EGCG may be protective agent against UV-induced cytotoxicity in HCE-T cells.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.