Atmospheric Pressure Plasma Treatment with Nitrogen Induces Osteoblast Differentiation and Reduces iNOS and COX-2 Expressions

: In recent years, atmospheric pressure plasma jet (APPJ) has been widely developed for various medical applica-tions, such as medical equipment sterilization, gene transfection, cell proliferation, and wound healing. In particular, non-thermal APPJ enables direct treatment of the biological system without any thermal-associated damage. The effect of cells on APPJ depends upon the gas species used in the treatment. However, the mechanisms underlying osteoblast differen tiation mediated by APPJ with nitrogen are yet to be studied. This study investigated the effects of nitrogen-APPJ on osteo blast differentiation by assessing the transcription factors, extracellular matrix proteins (ECMPs), alkaline phosphatase (ALP) activity, and the mRNA and protein expressions of ALP, inducible nitric oxide synthase (iNOS), and cyclooxygen-ase-2 (COX-2), in an osteoblast mouse cell line. We found that nitrogen-APPJ induced osteoblast differentiation-related transcription factors (runt-related transcription factor 2 [Runx2] and osterix), osteocalcin (OCN), and ALP activity, as well as reduced the mRNA and protein expressions of iNOS and COX-2. Thus, we concluded that APPJ affects differentiation of the osteoblast cells.