Comparison of biological effects on human keratinocytes using different plasma treatment regimes

Abstract

This study investigated the influence of the plasma treatment regime on human keratinocytes (HaCaT cells). HaCaT cells were plasma treated with a volume dielectric barrier discharge plasma source in three different ways: directly, directly with culture medium exchange, and indirectly (in which only cell culture medium was exposed to plasma). The influence of dielectric barrier discharge plasma on viability, DNA, cell cycle, and intracellular concentration of reactive oxygen species in HaCaT cells was investigated. Direct and indirect plasma treatment caused a treatment time–dependent decrease of viable cells. An increase in DNA damage was observed immediately after plasma treatment, which was diminished after 24 h. Intracellular reactive oxygen species increased with longer plasma treatment times. The cell cycle analysis showed an accumulation of cells in the G2/M phase at the expense of cells in the G1 phase. An immediate exchange of culture medium after plasma treatment attenuated the described effects. Direct and indirect plasma treatment of adherent HaCaT cells resulted in comparable effects that depend on the plasma treatment time. Physical plasma seems to generate long-living reactive species or to modify organic components of the cell culture medium. Both mechanisms can initiate oxidative stress in human keratinocytes, which is responsible for the observed effects.