【作者】 李昌敏；

【导师】 姜槐；

【作者基本信息】 浙江医科大学 ， 劳动卫生学， 1998， 博士

【摘要】 工频电磁场的生物学效应和对人体健康的影响，尤其是工频磁场对肿瘤发生发展的影响是当前生物电磁学研究的热点。研究复盖了流行病学调查、动物实验、细胞分子水平等多个层次。基于这些研究结果，有学者提出，工频磁场可能作用于促癌阶段。然而由于研究结果报道的不一致性以及对其促癌作用的机理和影响因素还很不清楚，对工频磁场是否存有促癌作用这个问题目前在国际上争论依然很大。 促癌过程可能是突变细胞的一种失控的无规则的生长形式，而细胞正常的生长增殖在一定程度上取决于它们与周围细胞的识别与通讯能力。细胞缝隙连接通讯(GJIC)是动物体内细胞通讯的重要方式之一，参与调控细胞的生长与分化。基于对GJIC与促癌关系的大量研究，有理由相信GJIC抑制是促癌过程的一个关键事件和重要机制。 本文拟用GJIC为观察指标，在以往研究的基础上，进一步探讨磁场可能存有的促癌作用或联合促癌作用及影响因素(时间、强度、波形、感应电场)。此外，对工频磁场引起的GJIC抑制的机理也进更多还原

【Abstract】 In bioelectromagnetics concern is rising on that if 50 Hz electromagnetic fields affect health, particularly 50 Hz magnetic fields （MFs） influence cancer development. On the bases of these studies at the level of epidemiology, intact animal, and molecule, some scientists pointed out that MFs might act as tumor promoter rather than initiator. However, the results are not constant, and the mechanism of MFs on cancer promotion and related factors are unknown, and therefore much conversy has been evoked at home and abroad.Cancer promotion might be a process resulting from an uncontroled growth of mutated cells. Growth of normal cells are dependent, to some extent on their ability to recognize cells, and perhaps on communication with neighboring cells. Gap junctional intercellular communication （GJIC） is one of important communication among cells in living system, and plays an essential role in regulation of cell growth and differentiation. Based on many studies related to the suppression of GJIC and cancer promotion, we reasonably believe that suppression of GJIC is key step in cancer promotion.In the present experiment, we used GJIC function as index to explore if 50 Hz MFs can act as cancer promoter or co-promoter, and to explore its related factors （e.g. magnetic flux density, exposure duration, waveform, and induced electric field）, and the mechanism of GJIC inhibition induced by MFs. 1) The effects of 50 Hz magnetic fields on GJIC and related factorsWe designed and established two sets of exposure systems （one is sinusoidal MFs and another 1:9 pulse MFs）, generating very uniform MFs in the central area （10cm×10 l×cm× 10cm） for cell exposure within a CO₂ incubator in which the magnetic flux densities could be regulated from 0 to 1.6 mT, and from 0 to 0.8 mT respectively. The magnetic flux densities were determined with a Model- 120 meter made in U.S.A. CHL or NIH/3T3 cells were routinely incubated in tissue culture dishes. When the cells just reached near confluence in the dishes for four days, the dishes were placed in the central area of the更多还原