Wound Healing Potential of Low Temperature Plasma in Human Primary Epidermal Keratinocytes

BACKGROUND: Low temperature plasma (LTP) was recently shown to be potentially useful for biomedical applications such as bleeding cessation, cancer treatment, and wound healing, among others. Keratinocytes are a major cell type that migrates directionally into the wound bed, and their proliferation leads to complete wound closure during the cutaneous repair/regeneration process. However, the beneficial effects of LTP on human keratinocytes have not been well studied. Therefore, we investigated migration, growth factor production, and cytokine secretion in primary human keratinocytes after LTP treatment. METHODS: Primary cultured keratinocytes were obtained from human skin biopsies. Cell viability was measured with the EZ-Cytox cell viability assay, cell migration was evaluated by an in vitro wound healing assay, gene expression was analyzed by quantitative real-time polymerase chain reaction, and protein expression was measured by enzyme-linked immunosorbent assays and western blotting after LTP treatment. RESULTS: Cell migration, the secretion of several cytokines, and gene and protein levels of angiogenic growth factors increased in LTP-treated human keratinocytes without associated cell toxicity. LTP treatment also significantly induced the expression of hypoxia inducible factor-1 alpha (HIF-1 alpha), an upstream regulator of angiogenesis. Further, the inhibition of HIF-1 alpha expression blocked the production of angiogenic growth factors induced by LTP in human keratinocytes. CONCLUSION: Our results suggest that LTP treatment is an effective approach to modulate wound healing-related molecules in epidermal keratinocytes and might promote angiogenesis, leading to improved wound healing.