title: Terahertz radiation at 0.380 THz and 2.520 THz does not lead to DNA damage in skin cells in vitro.
abstract: The question whether nonionizing electromagnetic radiation of low intensity can cause functional effects in biological systems has been a subject of debate for a long time. Whereas the majority of the studies have not demonstrated these effects, some aspects still remain unclear, e.g., whether high-frequency radiation in the terahertz range affects biological systems. In particular for frequencies higher than 0.150 THz, investigations of the ability of radiation to cause genomic damage have not been performed. In the present study, human skin cells were exposed in vitro to terahertz radiation at two specific frequencies: 0.380 and 2.520 THz. Power intensities ranged from 0.03-0.9 mW/cm(2) and the cells were exposed for 2 and 8 h. Our goal was to investigate whether the irradiation induced genomic damage in the cells. Chromosomal damage was not detected in the different cell types after exposure to radiation of both frequencies. In addition, cell proliferation was quantified and found to be unaffected by the exposure, and there was no increase in DNA damage measured in the comet assay for both frequencies. For all end points, cells treated with chemicals were included as positive controls. These positive control cells clearly showed decreased proliferation and increased genomic damage. The results of the present study are in agreement with findings from other studies investigating DNA damage as a consequence of exposure to the lower frequency range (<0.150 THz) and demonstrate for the first time that at higher frequencies (0.380 and 2.520 THz), nonionizing radiation does not induce genomic damage.
authors.affiliation: Institut für Pharmakologie und Toxikologie, Universität Würzburg, Germany.
authors.forename: Henning
authors.initials: H
authors.lastname: Hintzsche
authors.forename: Christian
authors.initials: C
authors.lastname: Jastrow
authors.forename: Bernd
authors.initials: B
authors.lastname: Heinen
authors.forename: Kai
authors.initials: K
authors.lastname: Baaske
authors.forename: Thomas
authors.initials: T
authors.lastname: Kleine-Ostmann
authors.forename: Michael
authors.initials: M
authors.lastname: Schwerdtfeger
authors.forename: Mohammed Khaled
authors.initials: MK
authors.lastname: Shakfa
authors.forename: Uwe
authors.initials: U
authors.lastname: Kärst
authors.forename: Martin
authors.initials: M
authors.lastname: Koch
authors.forename: Thorsten
authors.initials: T
authors.lastname: Schrader
authors.forename: Helga
authors.initials: H
authors.lastname: Stopper
mesh_terms: D002460:Cell Line; D020552:Comet Assay; D004249:DNA Damage; D006801:Humans; D015162:Micronucleus Tests; D012867:Skin / Q000166:cytology* / Q000378:metabolism / Q000528:radiation effects*; D055053:Terahertz Radiation / Q000009:adverse effects*