电磁场的非热生物效应及其机理研究

【作者】 田冰；

【导师】 陈树德；

【作者基本信息】 华东师范大学 ， 生物物理， 2004， 硕士

【摘要】 本实验室前期的研究结果表明，脉冲电场通过作用于胞间信使胰岛素，引发了生物效应——细胞增殖抑制，胰岛素下游信号酪氨酸激酶水平降低，以及基因表达的改变。本论文利用拉曼光谱，研究了脉冲电场作用后，胰岛素分子构象发生的改变，结果表明脉冲电场通过改变胰岛素分子的构象进而通过胰岛素信号通路引发生物效应。 工频磁场可以抑制细胞增殖，导致活细胞膜上EGFR发生聚集，同时实验观察到了工频磁场导致纯化的EGFR聚集，而EGFR是其所在信号转导通路中的关键一环。 上述两种电磁场生物效应的研究结果表明：弱的电磁场刺激可以通过作用于细胞信号系统引起宏观生物效应，这为合理解释非热效应机理提供了有力的实验依据。结合膜流动性变化的研究，我们可以推测电磁场作用位点：胞间信使，膜，膜上受体。 最后，结合细胞增殖实验，讨论了电磁场安全标准。我国现行的工频磁场标准是合理的(0.1mT辐照时间不超过8小时)。但是从理论计算的结果来看，工频磁场通过其感应电场引发生物效应的观点不成立。更多还原

【Abstract】 The 50Hz pulsed electric field (PEF) can cause a series of bio-effects: the decrease of binding ratio of insulin to its receptor, the suppressed level of tyrosine phosphorylation and the changes of gene expression. The conformation changes of insulin was detected by Raman spectrum after it was exposed to PEF. And results were consistent with the above bio-effects. From the view of cell signal transduction , insulin, as an intercellular signal molecule, transferred the effects of electric field into the cell through binding to its receptor. It is the way the PEF triggered bio-effects.50Hz sinusoidal magnetic field suppressed cell proliferation and caused EGFR (epidermal growth factor receptor )clustering on the membrane of CHL cell. Meanwhile the clustering of purified EGFR is observed after exposed to the magnetic field by AFM. And EGFR is a key point on the signal pathway.The conclusion can be reached that a weak EMF may lead to bio-effects through affecting signal pathways. And it reveals an important mechanism of the non-thermal EMF bio-effects .With the assay of membrane fluidity, we can presume that membrane, receptors and intercellular signal molecules are action sites of EMF.The current EMF exposure standard of 50Hz sinusoidal magnetic field in China is 0.1 mT and exposure time is less than 8 hours. The results of cell proliferation show it is safe . But theoretical calculation showed the assumption that magnetic fields act through its induced electric fields is not reasonable.更多还原