Effects of 5.8 GHz radiofrequency radiation on learning and memory along with synaptic plasticity of hippocampal neurons in rats

Objective: To investigate the effect of 5.8 GHz radiofrequency (RF) radiation on learning and memory along with hippocampal synaptic plasticity in rats, in order to provide theoretical and experimental references for scientific evaluation of potential hazards of 5.8 GHz RF radiation. Methods: A total of 56 healthy adult male Sprague-Dawley rats were randomly divided into sham exposure group (n = 28) and RF exposure group (n = 28). RF groups were exposed to 5.8 GHz RF for 1 h each day in 15 d or 30 d continuously, and the whole-body absorption rate was 1.15 W/kg. The learning and memory ability of rats was tested by Morris water maze (MWM). The hippocampal structure of rats was observed by Nissl stain. The density of dendritic spines in CA1 region of hippocampus was detected by Golgi stain. The expression of synaptic related protein (PSD95, Synaptophysin) in hippocampus was detected by Western blot. The level of hippocampal neurotransmitters was detected by liquid chromatography-mass spectrometry. Results: In MWM experiments, at 15 d and 30 d after RF exposure, there was no statistically significant difference between sham group and RF group in the escape latency, frequency of crossing plateau, percentage of stay time in plateau quadrant and latency of first arrival to the plateau (P > 0.05). Besides, the structure and the number of neurons in the hippocampus, the density of apical and basal dendritic spines of pyramidal neurons in the CA1 region (apical: 5.10 ± 0.20, 4.89 ± 0.24, 4.58 ± 0.27, 4.49 ± 0.24, and basal: 4.81 ± 0.17, 4.79 ± 0.34, 4.20 ± 0.27, 4.22 ± 0.17, named as Sham 15 d group, RF 15 d group, Sham 30 d group, RF 30 d group, respectively), the expression of PSD95 and Synaptophysin and the level of multiple kinds of neurotransmitters in the hippocampus had no significant changes (P > 0.05). Conclusions: In this study, 5.8 GHz RF radiation has no significant influence on the spatial learning and memory ability along with the synaptic plasticity of hippocampal neurons of rats. (authors)