The aim of this study was to investigate qualitative and quantitative changes in pyramidal and granule neurons in the male rat hippocampus after exposure to a continuous 900-megahertz (MHz) electromagnetic field (EMF) for 25 days during early and mid-adolescence. Three-week-old (21 day) healthy Sprague Dawley male rats were divided equally into control (CON), pseudo-exposed (PEX) and EMF groups. EMF rats were exposed to a 900-MHz EMF in an EMF-application cage, while the PEX rats were placed in the same cage without being exposed to EMF. No procedure was performed in CON. EMF was applied for 1 h/day, every day for 25 days. Following the 900-MHz EMF and pseudo-exposed applications, behavioral tests were performed for seven days. Then, all animals were euthanized and their brains were removed. Following histological tissue procedures, sections were taken from tissues and stained with toluidine blue. The optical fractionation technique was performed to estimate the pyramidal neuron numbers in the CA1, CA2-3 and hilus regions of the hippocampus and granule neuron numbers in the dentate gyrus region. Our findings indicated that the number of pyramidal and granule neurons in the hippocampus of the EMF group was statistically higher than PEX. Furthermore, the histopathological results showed that the cytoplasm of pyramidal (in the hilus, CA1, CA2 and CA3 region) and granular (in the dentate gyrus region) cells at the hippocampus were disrupted, as evident by intensive staining around cytoplasm and some artifacts were detected in the EMF group. In addition, statistical comparisons of the mean body weights and brain weights of the study groups revealed no significant differences. There was no statistically significant difference between the PEX and EMF groups in terms of temperature (p > 0.05) or humidity (p > 0.05) in the cages. In conclusion, higher numbers of both pyramidal and granule neurons were found in the male rat hippocampus after continuous 900-MHz EMF treatment.

中文翻译：

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青春期早期和中期暴露于连续 900 MHz 电磁场 7 天后大鼠海马锥体和颗粒神经元数量的变化

本研究的目的是调查在青春期早期和中期暴露于连续 900 兆赫 (MHz) 电磁场 (EMF) 25 天后雄性大鼠海马锥体和颗粒神经元的定性和定量变化。三周大 (21 天) 的健康 Sprague Dawley 雄性大鼠被平均分为对照组 (CON)、假暴露 (PEX) 和 EMF 组。EMF 大鼠在 EMF 应用笼中暴露于 900-MHz EMF，而 PEX 大鼠则被放置在同一个笼子中而不暴露于 EMF。在 CON 中没有进行任何程序。EMF 应用 1 小时/天，每天 25 天。在 900-MHz EMF 和伪暴露应用之后，行为测试进行了 7 天。然后，对所有动物实施安乐死并取出它们的大脑。在组织学组织程序之后，从组织中取出切片并用甲苯胺蓝染色。进行光学分级技术以估计海马的 CA1、CA2-3 和门区的锥体神经元数量以及齿状回区域的颗粒神经元数量。我们的研究结果表明，EMF 组海马中锥体和颗粒神经元的数量在统计学上高于 PEX。此外，组织病理学结果表明，海马的锥体细胞（在门、CA1、CA2 和 CA3 区域）和颗粒（在齿状回区域）细胞质被破坏，细胞质周围的强染色和一些伪影是明显的。在 EMF 组中检测到。此外，研究组的平均体重和脑重的统计比较显示没有显着差异。PEX 组和 EMF 组之间在笼子中的温度（p > 0.05）或湿度（p > 0.05）方面没有统计学上的显着差异。总之，在连续 900-MHz EMF 治疗后，雄性大鼠海马中发现了更多数量的锥体和颗粒神经元。