Soluble factor–mediated enhancement of cell viability via plasma-induced bystander effects

A previous study has shown that gaseous plasma treatment can induce non-monotonic cellular responses, in which cell viability initially decreases with incubation time after treatment but subsequently increases with longer incubation times. In this study, we investigated whether such behavior can be explained by bystander effects mediated by soluble factors released from plasma-treated cells. To this end, conditioned medium obtained from plasma-treated B16F10 and Colon 26 cells was transferred to untreated cells, and the resulting cellular responses were evaluated. The results demonstrated that soluble factors released from damaged cells significantly increased cell viability in untreated cells in a hormesis-like manner. Furthermore, similar responses were observed for 2 different plasma sources, suggesting that this phenomenon is not specific to a particular plasma source. These findings suggest that soluble factor-mediated bystander effects contribute to plasma-induced cellular responses and provide insight into the non-monotonic behavior observed following plasma treatment.