Abstract
The cataract is promoted by UV irradiation. It is well known that the main causes of UV induced cataract are reactive oxygen species which are generated by UV irradiation. Metallothionein (MTs) regulates detoxification from heavy metals, and free radical scavenging in living tissues. In this study, we analyzed the inductions of metallothionein-I (MT-I) and metallothionein-II (MT-II) by ZnCl2 treatment, and the protective effect of MTs against UV-A, UV-B and UV-C using mouse lens epithelial-derived cultured cells, alphaTN 4-1 cells. AlphaTN4-1 cells were treated by various concentration of ZnCl2, and then the expressions of MT-I and MT-II mRNA were analyzed by the real-time RT-PCR. ZnCl2 treated cells were irradiated by UV-A, UV-B and UV-C, and the cell viabilities were analyzed. The cell viabilities were measured by 3H-thymidine incorporation. This study revealed that MT-I and MT-II mRNA were induced concentration-dependently by ZnCl2 treatment, and induced MTs by ZnCl2 treatment significantly increased the cell viability against UV-A irradiation. This study indicates that a novel protection mechanism by MTs against UV-A may exist in the lens.
