An argon atmospheric pressure plasma jet was employed to treat L929 murine fibroblasts cultured in vitro. Experimental results showed that, compared with the control cells, the treatment of fibroblasts with 15 s of plasma led to a significant increase of cell viability and collagen synthesis, while the treatment of 25 s plasma resulted in a remarkable decrease. Exploration of related mechanisms suggested that cold plasma could up-regulate CyclinD1 gene expression and down-regulate p27 gene expression at a low dose, while it could down-regulate CyclinD1 expression and up-regulate p27 expression at a higher dose, thus altering the cell cycle progression, and then affecting cell viability and collagen synthesis of fibroblasts.

The potential antitumor application of low-temperature plasma (LTP) has attracted wide attention from researchers. The mechanism of plasma antitumor action may be related to LTP-induced reactive oxygen and nitrogen species. The aim of this study was to identify the apoptotic effects of plasma on melanoma cells (B16) in vivo and in vitro . For this purpose, a helium atmospheric-pressure plasma jet (APPJ) was used to generate the plasma-activated saline and medium (PAS and PAM). The PAS was injected subcutaneously to treat B16-tumor bearing mice in vivo and the PAM was used to treat B16 cells in vitro . Catalase (CAT) was added into the PAM to degrade H ₂ O ₂ as the intervention group. The tumor nodules’ weight, cryosections, B16 cell viability, apoptosis, DNA damage, p53 pathway-related protein and the concentration of H ₂ O ₂ in PAM were detected. The in vivo results showed that PAS could inhibit tumor growth and induce apoptosis. The in vitro results revealed the concentration of H ₂ O ₂ in the PAM increased as LTP treatment time was longer, while the cell viability decreased as APPJ irradiation time was increased. Flow cytometry results showed that, compared with the control group, all PAM treatment groups showed a higher apoptotic rate. A single cell gel assay and an 8-OHdG assay showed that the PAM could induce DNA damage. A western blotting assay indicated that the PAM could increase the expressions of p53, p53-induced gene 8 protein, PIG3, cytoplasmic cytochrome c, cleaved-caspase-9 and -3. However, CAT could alleviate all these changes effectively. These findings suggested that plasma exerted an apoptotic effect on B16 cells mainly by activating the p53/PIGs/caspase pathway.

As a representative technology in plasma medicine, cold atmospheric plasma (CAP) has beneficial outcomes in surface disinfection, wound repair, tissue regeneration, solid tumor therapy. Impact on immune response and inflammatory conditions was also observed in the process of CAP treatment. Relevant literatures were collected to assess efficacy and summarize possible mechanisms of the innovation. CAP mediates alteration in local immune microenvironment mainly through two ways. One is to down-regulate the expression level of several cytokines, impeding further conduction of immune or inflammatory signals. Intervening the functional phenotype of cells through different degree of oxidative stress is the other approach to manage the immune-mediated inflammatory disorders. A series of preclinical and clinical studies confirmed the therapeutic effect and side effects free of CAP. Moreover, several suggestions proposed in this manuscript might help to find directions for future investigation.