Wound response in fs-THz-irradiated mouse skin

Terahertz (THz) technology has emerged for biomedical applications such as scanning, molecular spectroscopy, and medical imaging. However, the biological effect of THz radiation is not fully understood. Non-thermal effects of THz radiation were investigated by applying a femtosecond-terahertz (fs-THz) pulse to mouse skin. Analysis of the genome-wide expression profile in fs-THz-irradiated skin indicated that wound responses were predominantly through NFκB1- and Smad3/4-mediated transcriptional activation. Repeated fs-THz radiation delayed the closure of mouse skin punch wounds due to up-regulation of transforming growth factor-beta (TGF-β). These findings suggest that fs-THz radiation provokes a wound-like signal in skin with increased expression of TGF-β and activation of its downstream target genes, which perturbs the wound healing process in vivo. To identify non-thermally induced in vivo mode action of THz radiation, gene expression profile of fs-THz-irradiated skin (at post 24-hours after 1 hour exposure) was explored. Purified total RNAs from independent 3 mice of each sham and THz group were labeled and hybridized on the Mouse Gene 1.0 ST Array (Affymetrix, Santa Clara, CA), according to manufacturer's standard protocol. Statistically filtered THz-responsive genes were examined for possible interactions with other molecules, canonical signaling pathways, and bio-functions.