PDF(Pubmed)
Abstract：
Background: With the global popularity of communication devices such as mobile phones, there are increasing concerns regarding the effect of radiofrequency electromagnetic radiation (RF-EMR) on the brain, one of the most important organs sensitive to RF-EMR exposure at 1,800 MHz. However, the effects of RF-EMR exposure on neuronal cells are unclear. Neurite outgrowth plays a critical role in brain development, therefore, determining the effects of 1,800 MHz RF-EMR exposure on neurite outgrowth is important for exploring its effects on brain development. Objectives: We aimed to investigate the effects of 1,800 MHz RF-EMR exposure for 48 h on neurite outgrowth in neuronal cells and to explore the associated role of the Rap1 signaling pathway. Material and Methods: Primary hippocampal neurons from C57BL/6 mice and Neuro2a cells were exposed to 1,800 MHz RF-EMR at a specific absorption rate (SAR) value of 4 W/kg for 48 h. CCK-8 assays were used to determine the cell viability after 24, 48, and 72 h of irradiation. Neurite outgrowth of primary hippocampal neurons (DIV 2) and Neuro2a cells was observed with a 20 × optical microscope and recognized by ImageJ software. Rap1a and Rap1b gene expressions were detected by real-time quantitative PCR. Rap1, Rap1a, Rap1b, Rap1GAP, and p-MEK1/2 protein expressions were detected by western blot. Rap1-GTP expression was detected by immunoprecipitation. The role of Rap1-GTP was assessed by transfecting a constitutively active mutant plasmid (Rap1-Gly_Val-GFP) into Neuro2a cells. Results: Exposure to 1,800 MHz RF-EMR for 24, 48, and 72 h at 4 W/kg did not influence cell viability. The neurite length, primary and secondary neurite numbers, and branch points of primary mouse hippocampal neurons were significantly impaired by 48-h RF-EMR exposure. The neurite-bearing cell percentage and neurite length of Neuro2a cells were also inhibited by 48-h RF-EMR exposure. Rap1 activity was inhibited by 48-h RF-EMR with no detectable alteration in either gene or protein expression of Rap1. The protein expression of Rap1GAP increased after 48-h RF-EMR exposure, while the expression of p-MEK1/2 protein decreased. Overexpression of constitutively active Rap1 reversed the decrease in Rap1-GTP and the neurite outgrowth impairment in Neuro2a cells induced by 1,800 MHz RF-EMR exposure for 48 h. Conclusion: Rap1 activity and related signaling pathways are involved in the disturbance of neurite outgrowth induced by 48-h 1,800 MHz RF-EMR exposure. The effects of RF-EMR exposure on neuronal development in infants and children deserve greater focus.
摘要：
背景:随着手机等通信设备的全球普及,人们越来越担心射频电磁辐射（RF-EMR）对大脑的影响，对1,800MHz的RF-EMR暴露敏感的最重要器官之一。然而,RF-EMR暴露对神经细胞的影响尚不清楚.神经突生长在大脑发育中起着关键作用，因此,确定1,800MHzRF-EMR暴露对神经突生长的影响对于探索其对大脑发育的影响很重要。目的：我们旨在研究1,800MHzRF-EMR暴露48h对神经元细胞神经突生长的影响，并探讨Rap1信号通路的相关作用。材料和方法：将来自C57BL/6小鼠的原代海马神经元和Neuro2a细胞以4W/kg的比吸收率（SAR）值暴露于1,800MHzRF-EMR中48h。CCK-8测定法用于确定照射24、48和72h后的细胞活力。用20倍光学显微镜观察原代海马神经元（DIV2）和Neuro2a细胞的神经元长出，并通过ImageJ软件进行识别。实时定量PCR检测Rap1a和Rap1b基因表达。Rap1,Rap1a,Rap1b,Rap1GAP,免疫印迹法检测p-MEK1/2蛋白表达。通过免疫沉淀检测Rap1-GTP表达。通过将组成型活性突变质粒(Rap1-Gly_Val-GFP)转染到Neuro2a细胞中来评估Rap1-GTP的作用。结果：在4W/kg下暴露于1,800MHzRF-EMR24、48和72h不会影响细胞活力。神经突长度，原发性和继发性神经突数量，48小时RF-EMR暴露后，原代小鼠海马神经元的分支点明显受损。48小时RF-EMR暴露也抑制了Neuro2a细胞的带有神经突的细胞百分比和神经突长度。Rap1活性被48小时RF-EMR抑制，Rap1的基因或蛋白质表达均未发生可检测到的变化。Rap1GAP蛋白表达在RF-EMR暴露48小时后增加,而p-MEK1/2蛋白表达降低。组成型活性Rap1的过表达逆转了1,800MHzRF-EMR暴露48h诱导的Rap1-GTP降低和神经突生长障碍。结论:Rap1活性和相关信号通路参与了48h1,800MHzRF-EMR暴露诱导的神经突生长障碍。RF-EMR暴露对婴儿和儿童神经元发育的影响值得更多关注。
