Liquid plasma as a treatment for cutaneous wound healing through regulation of redox metabolism

The skin functions as the outermost protective barrier to the internal organs and major vessels; thus, delayed regeneration from acute injury could induce serious clinical complications. For rapid recovery of skin wounds, promoting re-epithelialization of the epidermis at the initial stage of injury is essential, wherein epithelial keratinocytes act as leading cells via migration. This study applied plasma technology, which has been known to enable wound healing in the medical field. Through in vitro and in vivo experiments, the study elucidated the effect and molecular mechanism of the liquid plasma (LP) manufactured by our microwave plasma system, which was found to improve the applicability of existing gas-type plasma on skin cell migration for re-epithelialization. LP treatment promoted the cytoskeletal transformation of keratinocytes and migration owing to changes in the expression of integrin-dependent focal adhesion molecules and matrix metalloproteinases (MMPs). This study also identified the role of increased levels of intracellular reactive oxygen species (ROS) as a driving force for cell migration activation, which was regulated by changes in NADPH oxidases and mitochondrial membrane potential. In an in vivo experiment using a murine dorsal full-thickness acute skin wound model, LP treatment helped improve the re-epithelialization rate, reaffirming the activation of the underlying intracellular ROS-dependent integrin-dependent signaling molecules. These findings indicate that LP could be a valuable wound management material that can improve the regeneration potential of the skin via the activation of migration-related molecular signaling within the epithelial cell itself with plasma-driven oxidative eustress.