Effects of 20-MHz radiofrequency radiation on rat hematology, splenic function, and serum chemistry

In this study, Sprague-Dawley rats were exposed in a TEM chamber to 20-MHz (HF-band) continuous-wave radiofrequency radiation (RFR) for 6 hr/day, 5 days/week up to 6 weeks. The average E-field intensity was 2686 +/- 164 V/m (mean +/- SD) and the calculated specific absorption rate was 0.3 W/kg. Randomly sampled rats killed on Days 8, 22, 39, and 42 after initiation of exposure showed no statistically significant differences from controls for body mass, spleen cell density, erythrocyte and leukocyte counts, hematocrit, hemoglobin, methemoglobin, erythrocyte fragility, bilirubin, creatinine, SGPT, alkaline phosphatase, calcium, sodium, potassium, and spleen cell chemiluminescence. Splenic mass differences were statistically significant (p less than 0.05) only on Day 22. Spleen to body mass ratios differed significantly between exposed and control groups on Days 22 and 39 (P less than 0.05 and P less than 0.025, respectively). Histologic examination of the rats revealed the successive accumulation of phagocytic cells, lymphoid proliferation, development of lesions, and tissue necrosis characteristic of respiratory mycoplasmosis. In a followup experiment, a separate set of rats was exposed for 6 weeks to identical levels of RFR. No significant differences were found in splenic parameters and spleen cell peroxidative activity. Histologic examination of these animals revealed no evidence of mycoplasma infection. The observed differences between exposed and control animals of the first experiment appear to have resulted from subclinical respiratory mycoplasmosis rather than exposure to RFR.