Research on carcinogenesis modifying factor by static magnetic field exposure

我们先前已经发现，暴露在静磁场(SMF)中会增加微核的发生率。在本实验中，SMFS的联合暴露明显增加了几种诱变剂的微核率，这些诱变剂包括活性氧自由基诱导剂(阿霉素(DOX)、丝裂霉素C(MMC))。因此，SMFS对小鼠微核形成的增强作用可能与其诱导活性氧自由基有关。本研究采用小鼠骨髓微核试验，探讨抗氧化剂抗坏血酸(AS)能否控制SMF联合暴露对自由基致化学物质微核率的影响。结果表明：1)由于其本身不诱发任何微核；2)DOX或MMC的微核率因暴露于5 T SMF而增加。3)DOX和MMC的微核率均因联合暴露SMFS而增加。4)MMC和SMFS联合染毒引起的微核率在抗坏血酸预处理20分钟后显著降低。5)抗坏血酸对微核率的影响可维持至少72小时。6)SMFS染毒后骨髓细胞8-羟基-2‘-脱氧鸟苷(8-OHdG)水平升高，提示SMFS可诱发诱变相关自由基。这种效应可能会增加微核率。

We have previously found that exposure to static magnetic fields (SMFs) increase the frequency of micronuclei. In this experiment, it became clear that co-exposure to SMFs increases the frequency of micronuclei induction by several mutagens including active oxygen radical inducible chemicals (doxorubicin (DOX), mitomycin C (MMC)). Therefore, the increase in micronucleus formation by SMFs might be related to active oxygen radical inducibility. In the present study, we used the mouse bone marrow micronucleus test to investigate whether antioxidant (ascorbic acid (AS)) can control the effects of SMF co-exposure on the frequency of micronuclei produced by radical-inducing chemicals. As a result, the following were clarified.1)As itself did not induce any micronuclei.2)Frequency of micronuclei by DOX or MMC increased by exposure to 5 T SMFs.3)Frequency of micronuclei induced by both DOX and MMC was increased by co-exposure to SMFs, but these increases were blocked by pretreatment with ascorbic acid.4)Frequency of micronuclei induced by co-exposure to MMC and SMFs decreased strongly at 20 min interval of ascorbic acid pre-treatment.5)Effect of ascorbic acid on the micronucleus frequency was maintained for at least 72 hours.6)Increased levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in bone marrow cells was observed after exposure to SMFs.These results suggest that SMFs exposure triggers the induction of mutagen-related radicals. This effect might increase the micronucleus frequency.