Long-Term Study of 435 MHz Radio-Frequency Radiation on Blood-Borne End Points in Cannulated Rats. Part II: Methods, Results, and Summary

This study investigated the effects of long-term, low-level exposure to radio-frequency radiation (RFR) on various physiological systems in a large rodent population. Two hundred adult male white rats with chronically implanted aortic cannulas were randomly divided into two groups. Animals in the first group were exposed to the low-level RFR environment for approximately 22 hours daily, seven days a week, for six months. Depending on animal orientation within the home cage (all animals singly caged) the estimated whole-body specific absorption rate (SAR) ranged from 0.04 to 0.4 W/kg. The estimated mean whole-body SAR ranged from 0.3 W/kg (medium-sized rats) to 0.35 W/kg (large-sized rats). A second, sham-exposure group was maintained under identical conditions, but were not radiated. Microsamples of blood were withdrawn on a cyclic schedule from the unanesthetized and unrestrained rats. The blood samples were assayed for plasma adrenocorticotropin (ACTH), plasma corticosterone, plasma prolactin, plasma catecholamines (norepinephrine, epinephrine, and dopamine), hematological end points (hematocrit ratio, complete red blood cell count, complete white blood cell count, and a differential count of neutrophils, eosinophils, and monocytes), and cardiovascular end points (heart rate and mean arterial blood pressure). Analysis of the results showed no significant RFR-induced differences in these end points when the RFR-exposed group was compared to the sham-exposed group. Chronic exposure to the low-level, pulsed field resulted in no adverse effects on animal health, as measured by the spectrum of blood-borne end points.