Effects of long-term microwave irradiation on NMDAR, BDNF and related molecular expression in their signal pathways in rat hippocampus / 军事医学

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.

A aquaporin 4 expression and effects in rat hippocampus after microwave radiation / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the expression of aquaporin 4 (AQP4) after microwave exposure and the correlation with the brain injury by radiation.</p><p><b>METHODS</b>70 male rats were exposed to microwave whose average power density was 0, 10, 30 and 100 mW/cm(2) respectively. Rats were sacrificed at 6 h, 1 d, 3 d and 7 d after exposure. Immunohistochemistry and Western blot were used to detect the expression of AQP4 in protein level in rat hippocampus, and the expression of AQP4 in gene level was measured by in situ hybridization and RT-PCR.</p><p><b>RESULTS</b>The expression of AQP4 in rat hippocampus was abnormal after 10, 30, 100 mW/cm(2) microwave exposure. The protein level showed increased at first and then recovered at 10 and 30 mW/cm(2) groups, while increased progressively in 100 mW/cm(2) group within 14 d (P < 0.01). The gene expression of AQP4 was increased (0.51 +/- 0.02) at the beginning (6 h) and then regained after 10 mW/cm(2) microwave exposure, while in 30 and 100 mW/cm(2) groups, it rose to the peak at 7 d (0.46 +/- 0.02 and 0.43 +/- 0.08) and didn't get back (P = 0.004; P = 0.012).</p><p><b>CONCLUSION</b>Microwave radiation can increase the expression of AQP4 in rat hippocampus. The change might participate in the process of increasing permeability of blood-brain barrier and lead to the brain edema after microwave radiation.</p>

Influence of microwave radiation on synaptic structure and function of hippocampus in Wistar rats / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effect of microwave radiation on synaptic structure, characteristic of synaptosome, the contents and release of neurotransmitters in hippocampus in Wistar rats.</p><p><b>METHODS</b>Wistar rats were exposed to microwave radiation with average power density of 30 mW/cm(2). Electron telescope was used to study the change of the synaptic structure at 6 h after radiation and to identify synaptosome. Flow cytometry and electron spin resonance were used to study the change of the concentration of Ca(2+) in synapse and the fluidity of membrane proteins of synaptosome. High performance liquid chromatography (HPLC) and spectrophotometer were used to study the changes of contents and release of amino acids and acetylcholine in hippocampus.</p><p><b>RESULTS</b>Microwave radiation of 30 mW/cm(2) caused deposits of synapse vesicle, elongation of active zone, the increase of thickness of postsynaptic density (PSD) and curvature, and perforation of synapse. The concentration of Ca(2+) in synapse (P<0.01) and tc of membrane proteins (P<0.01) of synaptosome increased contents of glutamic acid and glycine (P<0.01) and release of GABA increased the increase of contents and release of acetylcholine, and activity of acetyl cholinesterase (P<0.01) increased.</p><p><b>CONCLUSION</b>Microwave radiation can induce the injure of synaptic structure and function of hippocampus, and then induce the disorder of the ability of learning and memory in rats.</p>

Studies on the injury effects of hippocampus induced by high power microwave radiation in rat / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the changes of morphology and function in rat hippocampus induced by high power microwave (HPM) radiation.</p><p><b>METHODS</b>Fifty male Wistar rats were radiated by HPM. Then their learning and memory abilities were tested with Y maze and were sacrificed 6 h, 1 d, 3 d and 7 d after radiation. The hippocampus was taken out to study the basic pathologic changes, apoptosis and the expressions of neuron-specific enolase (NSE) and glial fibrillary acidic protein (GFAP) by means of HE staining, Nissel body staining, in situ terminal end labeling and immunohistochemistry.</p><p><b>RESULTS</b>The learning and memory abilities of rats reduced significantly after HPM radiation. HPM also resulted in rarefaction, edema and hemangiectasia of hippocampus, nervous cells degeneration and necrosis, decrease or disappearance of Nissel bodies. The injuries were more serious in field CA4 and dentate gyrus, which showed dose-effect relationship, and were progressively aggravated within 7 days. The apoptosis cells were significantly increased. NSE was increased in neurons. The NSE positive areas were also seen in the interstitial matrix and blood vessels. GFAP was increased in astrocytes, which became shorter and thicker.</p><p><b>CONCLUSION</b>HPM can damage the abilities of learning and memory and results in morphologic changes in hippocampus. The major pathologic changes are degeneration, apoptosis and necrosis of neurons and edema in interstitium. NSE and GFAP play an important role in the pathologic process.</p>

The influence of high power microwave irradiation on the expression of neuropeptide Y and neural nitric oxide synthase in the rat cerebral cortex and hippocampus / 中华物理医学与康复杂志

Objective To investigate the effect of high power microwave(HPM) irradiation on neuropeptide Y (NPY) and neural nitric oxide synthase (nNOS) expression in the cerebral cortex and hippoeampus of Wistar rats. Methods A total of 110 Wistar rats were used for this study.Three groups of 30 Wistar rats were exposed to HPM irradiation at intensities of 3,10,30 and 100 mW/cm~2,respectively.Twenty rats served as controls and were ex- posed to sham HPM irradiation.At 6 h,and at 1,3,7,14 and 28 d after irradiation,five rats from each group were sacrificed,and their cerebral cortices and hippocampi were harvested.HE staining was used to highlight any change in the structure of the cerebral cortex or hippocampus.Immunohistochemistry techniques and image analysis were used to study the changes in NPY and nNOS expression.Results 10 to 100 mW/cm~2 HPM irradiation caused pyc- nosis and deep staining of some neurons in the cerebral cortex and hippocampus.The increase in nNOS expression and decrease in NPY expression observed were significant at 3 days after irradiation.Conclusion HPM irradiation can induce injury in neurons of the cerebral cortex and hippoeampus,and abnormal NPY and nNOS expression.