次级视觉皮层组织病理学改变和神经元钙活动增强参与微波辐射致焦虑样行为

Histopathological changes in secondary visual cortex and enhanced calcium activity in neurons being involved in microwave radiation⁃induced anxiety⁃like behavior

目的阐明微波辐射对焦虑样情绪行为以及次级视觉皮层组织结构和神经元钙活动的影响。方法选取C57BL/6N小鼠36只,按照随机数表法分为对照组和微波辐射组,其中单纯行为学检测对照组8只,辐射组7只;光纤记录结合行为学实验对照组8只,辐射组7只;苏木素⁃伊红(HE)染色每组各3只。采用中心频率9.875 GHz,平均功率密度12 mW/cm^(2)的X波段高功率微波模拟源,辐射15 min,建立微波辐射动物模型。利用旷场和高架十字迷宫实验,检测微波辐射后小鼠焦虑样情绪行为改变。采用HE染色和光学显微镜观察,研究微波辐射对次级视觉皮层组织形态学结构的影响。基于遗传编码钙成像技术,通过光纤记录结合旷场、高架十字迷宫行为学范式,检测次级视觉皮层V2M区神经元钙活动变化。结果微波辐射后,辐射组小鼠探索旷场中央区域次数及高架十字迷宫开放臂次数较对照组下降,差异均有统计学意义(t=2.24、3.10,P<0.05);辐射组小鼠次级视觉皮层部分神经元变性、凋亡,主要表现为核固缩深染,胞体皱缩,血管周间隙略增宽。光纤记录结合行为学实验结果表明,微波辐射后小鼠探索旷场中央区域与对照组比较差异有统计学意义(t=-2.75,P<0.05);高架十字迷宫开放臂时辐射组对照组和辐射前比较,差异也均有统计学意义(t=-2.77、-3.41,P<0.05)。次级视觉皮层神经元钙活动均显著增强。结论微波辐射可导致焦虑样行为发生以及次级视觉皮层组织的病理学改变,次级视觉皮层神经元钙活动增强是微波辐射致焦虑样行为改变的重要机制。

Objective To clarify the effects of microwave radiation on anxiety⁃like behavior,the histomorphology of the secondary visual cortex,and calcium activity in neurons.Methods 36 C57BL/6N mice were selected and divided into control group and microwave radiation group according to the random number table method.In the simple behavioral testing,there were 8 mice in the control group and 7 mice in the radiation group.Combining fiber optic recording with behavioral experiments,there were 8 mice in the control group and 7 mice in the radiation group.Hematoxylin⁃eosin(HE)staining was conducted with 3 mice in each group.A high⁃power microwave simulated source in the X⁃band with a center frequency of 9.875 GHz and an average power density of 12 mW/cm^(2) was used to irradiate the mice for 15 minutes,establishing a microwave radiation animal model.Then,anxiety⁃like behavior changes in the radiation group were identified using the open⁃field and elevated plus maze(EPM)tests.The effects of microwave radiation on the histomorphology of the secondary visual cortex were investigated using HE staining and optical microscopy.Based on the genetically encoded calcium imaging technique,as well as optical fiber recording combined with behavioral paradigms in the open field and the EPM,the changes of calcium activity in neurons in the V2M region of the secondary visual cortex were detected.Results Compared to the control group,the radiation group showed a significant decrease in the frequency of exploring the central region of the open field and the open arm of the EPM(t=2.24,3.10,P<0.05).Furthermore,the radiation group exhibited the degeneration and apoptosis of some neurons in the secondary visual cortex,primarily manifested as pyknosis and deep staining,cell body shrinkage,and the slightly widening of perivascular space.Fiber optic recordings and behavioral experiments indicated that compared to the control group,mice in the radiation group exhibited significantly increased calcium activities in neurons of the secondary visual cortex when exploring the central region of the open field(t=-2.75,P<0.05)or the open arm of the EPM(t=-2.77,-3.41,P<0.05)compared to those before radiation after microwave exposure.Conclusions Microwave radiation can induce anxiety⁃like behaviors and histopathological changes in the secondary visual cortex.Increased calcium activity in neurons of the secondary visual cortex is proved to be an important mechanism underlying the changes in anxiety⁃like behavior due to microwave radiation.