| Summary: | 碩士 === 國防醫學院 === 生物化學研究所 === 104 === Dermis is principally made of fibroblasts. In addition to natural aging occurred in all organs, sunlight exposure is a harmful factor to cause extra damage to dermal fibroblast, particularly the exposure to ultraviolet (UV) B irradiation. Because of the toxicity of iron, another transition metal copper may stem from Fenton reaction as iron does. In this study, we investigated whether copper chelator protected dermal fibroblast from UVB irradiation induced oxidative stress and apoptosis. In addition to using commercial available copper chelators, tetrathiomolybdate and disulfiram, a newly synthesized compound HLH2 was also examined. We found that UVB irradiation (15 mJ /cm2) stops the growth of dermal fibroblast, increased cellular reactive oxygen species (ROS) generation and malondialdehyde level, AP-1 protein level, mmp-1 protein level, and caused apoptosis. Compound HLH2 itself, up to 1 μM, had no harmful effect on cells growth of dermal fibroblast, while displayed protective effect from UVB irradiation induced growth inhibition with an EC50 (50% of maximal effective concentration) value of 0.3 μM and the maximal effective concentration of 1μM. Consistently, compound HLH2 also blocked UVB irradiation induced cellular ROS and malondialdehyde generation. In parallel with the increased ROS generation, 32% cells were found to be dead at 24 h after UVB irradiation compared to 5% of control cells and this effect of UVB irradiation was significantly inhibited by compound HLH2 treatment, 9% cells being dead. Disulfiram (0.1μM) inhibited cell growth as effective as UVB irradiation. Tetrathiomolybdate (3 μM) blocked the harmful effect induced by both UVB irradiation and disulfiram treatment in dermal fibroblast, while compound HLH2 could not protect cells from disulfiram induced growth inhibition.
In this study, we demonstrate that HLH2 can reduce the damage causing by UVB is calcium-dependent but not copper. We confirmed that UVB increase in intracellular calcium via TRPV1 ion channel. HLH2 can reduce cell apoptosis thought inhibit intracellular calcium level.
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