Effects of radio-frequency radiation on inflammation

Inflammatory responses, which were induced in rats by a subcutaneous injection of sheep red blood cells (SRBC) into footpads, and in mice, by tail-vein trauma due to sequential bleeding, were observed in animals that had been pretreated wth 26-MHz radio-frequency radiation (RFR) or with a frank thermal burden. Pretreatment of rats by RFR decreased the severity of SRBC-induced inflammation; averaged thickness of the footpad was less by 33.0% and 45.6%, respectively, than thicknesses observed in thermally treated and control animals. White blood cell (WBC) counts in RFR pretreated, tail-vein traumatized mice remained constant, in contrast to the leukocytosis that was observed in air-heated and in sham-exposed animals. Moreover, the inflammatory response in RFR-treated mice was accompanied by a well-defined but transient refractory state in the number of circulating specialized leukocytes. The 92-hour time course of the refractory state was characterized by a transient fourfold decrease of lymphocytes and a fourfold increase of neutrophils that peaked three hours after exposure; these changes were in marked contrast to those observed in thermal and passive controls. The results indicate that RFR can attenuate an inflammatory reaction. This inhibitory property may have relevance to immunocompetency of cell-mediated immunity (CMI), since CMI responses invoke nonspecific inflammatory reactions.