Inhibition of Inflammation by an Air-Based No-Ozone Cold Plasma in TNF-α-Induced Human Keratinocytes: An In Vitro Study

<b>Background/Objectives</b>: Recent studies have reported the effectiveness of cold plasma technology in treating skin inflammation and wounds. We investigated the effect of an air-based no-ozone cold plasma device (Air NCP) on the inflammatory response in human keratinocytes (HaCaT). <b>Methods</b>: The cytotoxicity of Air NCP was assessed using the sulforhodamine B assay, and its ozone concentration and operating temperature were measured to evaluate safety. To determine its anti-inflammatory effect, inflammation was induced with tumor necrosis factor-alpha (TNF-α), and changes in inflammation-related gene expression were analyzed using reverse transcription-polymerase chain reaction and Western blot analysis. The level of prostaglandin E2 (PGE2), an indicator of inflammation, was measured using an enzyme-linked immunosorbent assay. <b>Results</b>: Air NCP showed no cytotoxicity in HaCaT cells. Moreover, the expression of TNF-α, interleukin-6, and interleukin-1β significantly decreased following treatment (<i>p</i> < 0.001). The levels of phosphorylated nuclear factor kappa B and phosphorylated signal transducer and activator of transcription-3 were also reduced (<i>p</i> < 0.001). Western blot analysis further confirmed that inflammation-activated mitogen-activated protein kinase factors were reduced by Air NCP, while cyclooxygenase-2 and PGE2 levels similarly decreased. <b>Conclusions</b>: These results indicate that Air NCP treatment suppresses the expression of inflammatory mediators in skin inflammation, demonstrating a clear anti-inflammatory effect.