ABSTRACT
Objective To evaluate the effect of long-term microwave radiation on the expression of N-methyl-D-aspartate receptor(NMDAR),brain derived neurotrophic factor(BDNF) and related molecules in signal pathways in the hippocampus of rats.Methods Fifty male Wistar rats were exposed to microwave radiation at an average power density of 0,5,10,20 and 30 mW/cm2for 6 min/time,3 times/week,and for 6 weeks,which were sacrificed and the hippocampus was quickly removed at 14 d and 28 d after exposure.The changes in NMDAR (NR1,NR2A,NR2B),postsynaptic density protein(PSD)-95,cortactin,BDNF and tyrosine kinase receptor B (TrkB) in hippocampal neurons of each group were detected by Western blotting and image analysis techniques.Results Compared with the control group,the expressions of related proteins did not change significantly after microwave irradiation of 5 mW/cm2 at each time point.After 20 mW/cm2 microwave radiation,the expression of NR1 was increased at 14 and 28 d (P ＜0.05),the expression of NR2A was increased at 28 d (P ＜ 0.05),but the expression of NR2B was decreased at 14 and 28 d (P ＜ 0.05).At a average power density of 30 mW/cm2,the expressions of NR1,NR2A and PSD-95 and the expression of NR2B were decreased at 14 and 28 d(P ＜0.05),and cortactin,BDNF and TrkB were increased at 14 d after irradiation (P ＜ 0.05).Conclusion The effect of different dosages of long-term microwave radiation on the proteins of NMDAR and its signal pathway related molecules is different.Microwave radiation may affect the NMDAR of postsynaptic information transmission through the BDNF-TrkB signaling pathways,which might play an important role in the impediment of learning and memory function caused by microwave radiation.