It was reported that exposure to microwave at a single frequency could induce behavioral changes, however, the effect of combined microwave exposure with multiple frequencies on behavior remain unclear. In this study, mice were exposed to either S-band (3.5 GHz) microwave (S group) or C-band (4.9 GHz) microwave (C group), or combined exposure to both S-band and C-band microwave (SC group), all for 5 weeks (1 h per day) at a power density of 50 W/m2. Following exposure, anxiety-like, depression-like and cognitive behaviors were evaluated. The morphological structure of the hippocampus and amygdala were observed, along with levels of NLRP3 inflammasome dependent pyroptosis. Additionally, alterations in blood-brain barrier (BBB) and synapses in the amygdala were examined. The results showed that compared with Sham group, all three exposure groups exhibited increased anxiety-like behavior in mice. Compared with S group, the anxiety level in C group and SC groups were much higher. However, anxiety levels in the SC group were lower than those in C group. Furthermore, NLRP3 inflammasome-dependent neuronal pyroptosis was observed in both the hippocampus and amygdala of all exposed mice, and the SC group exhibited the most severe brain damage in hippocampal CA3 region, whereas the C group exhibited the greatest amygdala pathology and BBB disruption. In summary, these findings suggest that NLRP3 inflammasome-mediated neuronal pyroptosis in the hippocampus and amygdala underlies microwave-induced anxiety, and amygdala-specific pyroptosis may play a more dominant role in driving anxiety-like behaviors than hippocampal damage under these exposure conditions. Additionally, combined microwave exposure may produce antagonistic biological effects.
Zhou et al. (2026) studied this question.