We investigated the effects on human keratinocytes (HaCaT) of exposure to a sinusoidal magnetic field of 2 mT (50 Hz). These cells are a good model for studying interaction of nonionising radiation, because they are not shielded from fields in vivo and also because they are resistant to both mechanical and thermal stimuli. We performed scanning microscopy which showed modification in shape and morphology in exposed cells. This modification is related to differential actin distribution as revealed by phalloidin fluorescence analysis. Moreover, the exposed cells show increased clonogenic capacity, as well as increased cellular growth as showed by clonogenicity assays and growth curves. Indirect immunofluorescence analysis using a fluorescent antibody against involucrin and beta4 integrin, which are respectively differentiation and adhesion markers, revealed an increase of involucrin expression and segregation of beta4 integrin in the cell membrane in cells exposed to 50 Hz; a higher percentage of the exposed cells shows a modified pattern of adhesion and differentiation markers. We also present evidence that exposure of HaCaT cells can interfere with protein kinase activity. Our observations confirm the hypothesis that electromagnetic fields at 50 Hz may modify cell membrane morphology and interfere with initiation of the signal cascade pathway and cellular adhesion.

中文翻译：

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极低频（50 Hz）磁场对人角质形成细胞形态和生化特性的影响。

我们调查了暴露于2 mT（50 Hz）的正弦磁场对人角质形成细胞（HaCaT）的影响。这些细胞是研究非电离辐射相互作用的一个很好的模型，因为它们没有被体内的磁场屏蔽，还因为它们对机械和热刺激均具有抵抗力。我们进行了扫描显微镜检查，显示暴露细胞的形状和形态发生了改变。如鬼笔环肽荧光分析所揭示的，该修饰与肌动蛋白的差异分布有关。而且，暴露的细胞表现出增加的克隆形成能力，以及增加的细胞生长，如克隆形成性测定和生长曲线所示。使用针对分别为分化和粘附标志物的整合素和beta4整合素的荧光抗体进行的间接免疫荧光分析，揭示了暴露于50 Hz的细胞中整合素表达的增加和β4整合素在细胞膜中的分离; 较高百分比的暴露细胞显示出粘附和分化标记物的修饰模式。我们还提供证据表明，HaCaT细胞的暴露会干扰蛋白激酶的活性。我们的观察结果证实了以下假设：50 Hz的电磁场可能会改变细胞膜的形态，并干扰信号级联途径和细胞粘附的启动。