Gene expression changes in the skin of rats induced by prolonged 35 GHz millimeter-wave exposure.
To better understand the cellular and molecular responses to overexposure to millimeter waves, alterations in the gene expression profile and histology of skin after exposure to 35 GHz radiofrequency radiation were investigated. Rats were subjected to sham exposure, to 42 degrees C environmental heat, or to 35 GHz millimeter waves at 75 mW/cm(2). Skin samples were collected at 6 and 24 h after exposure for Affymetrix GeneChip analysis. The skin was harvested from a separate group of rats at 3-6 h or 24-48 h after exposure for histopathology analysis. Microscopic findings observed in the dermis of rats exposed to 35 GHz millimeter waves included aggregation of neutrophils in vessels, degeneration of stromal cells, and breakdown of collagen. Changes were detected in 56 genes at 6 h and 58 genes at 24 h in the millimeter-wave-exposed rats. Genes associated with regulation of transcription, protein folding, oxidative stress, immune response, and tissue matrix turnover were affected at both times. At 24 h, more genes related to extracellular matrix structure and chemokine activity were altered. Up-regulation of Hspa1a, Timp1, S100a9, Ccl2 and Angptl4 at 24 h by 35 GHz millimeter-wave exposure was confirmed by real-time RT-PCR. These results obtained from histopathology, microarrays and RT-PCR indicate that prolonged exposure to 35 GHz millimeter waves causes thermally related stress and injury in skin while triggering repair processes involving inflammation and tissue matrix recovery.
Millenbaugh
Nancy J
NJ
General Dynamics Advanced Information Systems, San Antonio, Texas 78235, USA. nancy.millenbaugh.ctr@brooks.af.mil
Roth
Caleb
C
Sypniewska
Roza
R
Chan
Victor
V
Eggers
Jeffrey S
JS
Kiel
Johnathan L
JL
Blystone
Robert V
RV
Mason
Patrick A
PA
D000818:Animals; D016207:Cytokines / Q000378:metabolism; D004307:Dose-Response Relationship, Radiation; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D005786:Gene Expression Regulation / Q000502:physiology* / Q000528:radiation effects*; D006360:Heat-Shock Proteins / Q000378:metabolism; D006358:Hot Temperature; D008297:Male; D008872:Microwaves; D011829:Radiation Dosage; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012867:Skin / Q000378:metabolism* / Q000528:radiation effects*; D012881:Skin Temperature / Q000528:radiation effects*
D016207:Cytokines; D016326:Extracellular Matrix Proteins; D006360:Heat-Shock Proteins; D017382:Reactive Oxygen Species