ABSTRACT
OBJECTIVE@#To estimate the detrimental effects of shortwave exposure on rat hippocampal structure and function and explore the underlying mechanisms.@*METHODS@#One hundred Wistar rats were randomly divided into four groups (25 rats per group) and exposed to 27 MHz continuous shortwave at a power density of 5, 10, or 30 mW/cm2 for 6 min once only or underwent sham exposure for the control. The spatial learning and memory, electroencephalogram (EEG), hippocampal structure and Nissl bodies were analysed. Furthermore, the expressions of N-methyl-D-aspartate receptor (NMDAR) subunits (NR1, NR2A, and NR2B), cAMP responsive element-binding protein (CREB) and phosphorylated CREB (p-CREB) in hippocampal tissue were analysed on 1, 7, and 14 days after exposure.@*RESULTS@#The rats in the 10 and 30 mW/cm2 groups had poor learning and memory, disrupted EEG oscillations, and injured hippocampal structures, including hippocampal neurons degeneration, mitochondria cavitation and blood capillaries swelling. The Nissl body content was also reduced in the exposure groups. Moreover, the hippocampal tissue in the 30 mW/cm2 group had increased expressions of NR2A and NR2B and decreased levels of CREB and p-CREB.@*CONCLUSION@#Shortwave exposure (27 MHz, with an average power density of 10 and 30 mW/cm2) impaired rats' spatial learning and memory and caused a series of dose-dependent pathophysiological changes. Moreover, NMDAR-related CREB pathway suppression might be involved in shortwave-induced structural and functional impairments in the rat hippocampus.
Subject(s)
Animals , Male , Rats , Cyclic AMP Response Element-Binding Protein , Genetics , Metabolism , Dose-Response Relationship, Radiation , Electroencephalography , Radiation Effects , Hippocampus , Radiation Effects , Memory , Radiation Effects , Nissl Bodies , Physiology , Radiation Effects , Radio Waves , Random Allocation , Rats, Wistar , Receptors, N-Methyl-D-Aspartate , Genetics , Metabolism , Spatial Learning , Radiation EffectsABSTRACT
<p><b>OBJECTIVE</b>To detect the effects of microwave on calcium levels in primary hippocampal neurons and primary cardiomyocytes by the real-time microwave exposure combined with laser scanning confocal microscopy.</p><p><b>METHODS</b>The primary hippocampal neurons and primary cardiomyocytes were cultured and labeled with probes, including Fluo-4 AM, Mag-Fluo-AM, and Rhod-2, to reflect the levels of whole calcium [Ca2+], endoplasmic reticulum calcium [Ca2+]ER, and mitochondrial calcium [Ca2+]MIT, respectively. Then, the cells were exposed to a pulsed microwave of 2.856 GHz with specific absorption rate (SAR) values of 0, 4, and 40 W/kg for 6 min to observe the changes in calcium levels.</p><p><b>RESULTS</b>The results showed that the 4 and 40 W/kg microwave radiation caused a significant decrease in the levels of [Ca2+], [Ca2+]ER, and [Ca2+]MIT in primary hippocampal neurons. In the primary cardiomyocytes, only the 40 W/kg microwave radiation caused the decrease in the levels of [Ca2+], [Ca2+]ER, and [Ca2+]MIT. Primary hippocampal neurons were more sensitive to microwave exposure than primary cardiomyocytes. The mitochondria were more sensitive to microwave exposure than the endoplasmic reticulum.</p><p><b>CONCLUSION</b>The calcium efflux was occurred during microwave exposure in primary hippocampal neurons and primary cardiomyocytes. Additionally, neurons and mitochondria were sensitive cells and organelle respectively.</p>