Magnesium ascorbyl phosphate and coenzyme Q 10 protect keratinocytes against UVA irradiation by suppressing glutathione depletion

The aim of this study was to investigate whether magnesium ascorbyl phosphate (MAP) and coenzyme Q<inf>10</inf> (CoQ<inf>10</inf>) 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 CoQ<inf>10</inf> was added at concentrations of 2.5, 5 and 10 μM, respectively. The results revealed that CoQ<inf>10</inf> 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 CoQ<inf>10</inf> 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 CoQ<inf>10</inf> was added at concentrations of 2.5, 5 and 10 μM, respectively. These results imply that MAP and CoQ<inf>10</inf> can protect the keratinocytes against UVA irradiation, possibly via increasing the levels of GSH.