Long-term effects of 2.45-GHz radiation on the ultrastructure of the cerebral cortex and on hematologic profiles of rats

A multimode microwave (MW) exposure chamber was employed to investigate the effects of multiple exposures to low-intensity CW radiation on the ultrastructure of the cerebral cortex of female Sprague-Dawley rats. In order to maximize the opportunity to observe long-term structural changes, a 6-week recovery period was interposed between the last of 110 daily MW-exposure sessions and the preparation of tissue samples for subsequent electron microscopic examination. Relative to sham-irradiated control subjects, exposure to 2.45-GHz radiation at an averaged specific absorption rate (SAR) of 2.3 mW/g produced a statistically significant increase in the occurrence of myelin figures in cortical dendrites of irradiated animals. No other remarkable structural changes were observed. Hematologic analyses revealed a significant elevation in the RBC counts of irradiated rats; differential WBC counts produced evidence of several marginally significant irregularities. Periodic samples of rectal temperature obtained during the course of irradiation revealed no indication of whole-body heating.