Calcium signaling in UV-induced damage

摘要

Hepal-6 cells were irradiated with UV and incubated for varying periods of time. [Ca~(2+)]_i (intracellular calcium concentration) of UV-irradiated cell was measured by ratio fluorescence imaging system. The comet assay was used to determine DNA damage. During the UVB-irradiation, [Ca~(2+)]_i had an ascending tendency from 0.88 J/m~2 to 92.4J/m~2. Comet assay instant test indicated that when the irradiation dosage was above 0.88J/m~2, DNA damage was observed. Even after approximate 2 h of incubation, DNA damage was still not detected by 0.88J/m~2 of UVB irradiation. During UVA-irradiation, the elevation of [Ca~(2+)]_i was not dose-dependent in a range of 1200 J/m~2-6000J/m~2 and DNA damage was not observed by comet assay. These results suggested that several intracellular UV receptors might induce [Ca~(2+)]_i rising by absorption of the UV energy. Just [Ca~(2+)]_i rising can't induce DNA damage certainly, it is very likely that the breakdown of calcium steady state induces DNA damage.