Magnesium ascorbyl phosphate and coenzyme Q10 protect keratinocytes against UVA irradiation by suppressing glutathione depletion.

The aim of this study was to investigate whether magnesium ascorbyl phosphate (MAP) and coenzyme Q10 (CoQ10) can protect keratinocytes against ultraviolet (UV)A irradiation by increasing the levels of glutathione (GSH). The cell survival fraction was 89.9% when the keratinocytes were irradiated with UVA at a dose of 4 J/cm2. The cell survival fractions were 48.4, 9.1 and 4.8%, at doses of 8, 16 and 32 J/cm2, respectively. MAP was added to the cells prior to UVA irradiation at a dose of 8 J/cm2 and then the cell viability was assayed. The cell survival fractions were 51.6, 55.5, 64.8 and 76.7%, when MAP was added at concentrations of 125, 250, 500 µM and 1 mM, respectively. The results showed that MAP is capable of protecting keratinocytes against UVA irradiation. The cell survival fractions were 77.2, 89.4 and 90.1%, when CoQ10 was added at concentrations of 2.5, 5 and 10 µM, respectively. The results revealed that CoQ10 is capable of protecting keratinocytes against UVA irradiation. At the same time, the levels of GSH within cells were detected. The level of GSH within cells was 0.3 mmol/g protein when the keratinocytes were irradiated with UVA at a dose of 8 J/cm2. We measured the levels of GSH within the cells after MAP or CoQ10 was added prior to UVA irradiation at a dose of 8 J/cm2. The levels of GSH within the cells were 0.344, 0.388, 0.456 and 0.5 mmol/g protein, when MAP was added at concentrations of 125, 250, 500 µM and 1 mM, respectively. The levels of GSH within the cells were 0.328, 0.35 and 0.394 mmol/g protein, when CoQ10 was added at concentrations of 2.5, 5 and 10 µM, respectively. These results imply that MAP and CoQ10 can protect the keratinocytes against UVA irradiation, possibly via increasing the levels of GSH.