A Nonclinical Safety Evaluation of Cold Atmospheric Plasma for Medical Applications: The Role of Genotoxicity and Mutagenicity Studies.

Atmospheric nonthermal plasma (ANTP) has rapidly evolved as an innovative tool in biomedicine with various applications, especially in treating skin diseases. In particular, the formation of reactive oxygen species (ROS) and nitrogen species (RNS), which are generated by ANTP, plays an important role in the biological signaling pathways of human cells. Unfortunately, excessive amounts of these reactive species significantly result in cellular damage and cell death induction. To ensure the safe application of ANTP, preclinical in vitro studies must be conducted before proceeding to in vivo or clinical trials involving humans. Our study aimed to investigate adverse effects on genetic substances in murine fibroblast cells exposed to ANTP. Cell viability and proliferation were markedly reduced after exposing the cells with plasma. Both extracellular and intracellular reactive species, especially RNS, were significantly increased upon plasma exposure in the culture medium and the cells. Notably, significant DNA damage in the cells was observed in the cells exposed to plasma. However, plasma was not classified as a mutagen in the Ames test. This suggested that plasma led to the generation of both extracellular and intracellular reactive species, particularly nitrogen species, which affect cell proliferation and are also known to induce genetic damage in fibroblast cells. These results highlight the genotoxic and mutagenic effects of ANTP, emphasizing the need for the cautious selection of plasma intensity in specific applications to avoid adverse side effects resulting from reactive species production.