Effects of terahertz exposure on skin injury in mouse model

Abstract

Objective To explore the characteristics of biological effects of terahertz (THz) exposure on the skin injury, and investigate the underlying mechanisms. Methods The hair-removed skin of C57BL/6J mice were exposed to 0.22 THz irradiation, at an average power density of 0, 25 and 50 mW/cm2, respectively, for 5 min. The temperature curve and pathological changes in the exposed area were observed and analyzed. The gene expression in the skin area was detected using RNA-seq analysis and bioinformatics analysis for global changes of the impairment and underlying molecular mechanisms. Finally, ELISA was used to verify inflammatory responses in the skin revealed by RNA-seq. Results Though 25 mW/cm2 THz irradiation did not induce obvious temperature change, 50 mW/cm2 THz irradiation exposure significantly raised the temperature higher than 2 ℃, and caused epithelial detachment and bleeding in the exposed area. RNA-seq analysis found 49 genes up-regulated and 27 genes down-regulated in the injured skin area. The following Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that these genes were majorly involved in immune responses and inflammatory responses. The results of ELISA indicated that the expression levels of IL-1β, IL-6, and TNF-α were increased remarkably after exposure. Conclusion THz irradiation exposure causes significant thermal effects and other injuries, including inflammatory responses, and induces abnormal expression of a series of genes in the exposed skin area.

Keywords

• terahertz
• skin
• thermal effect
• wounds and injuries
• rna-seq analysis
• inflammatory response