旋转磁场对放射损伤小鼠血清自由基的影响

Effect of rotation magnetic field on free radicals in radiation-injured mice serum

背景：已证实磁场可提高放射损伤小鼠的存活率和存活期，而大量自由基产生是放射损伤的机制之一，因此推测磁场对自由基可能存在一定的作用。目的：观察旋转磁场对放射损伤小鼠血清超氧化物歧化酶活力、丙二醛浓度的影响。设计、时间及地点：随机对照动物实验，于2007-04/08在解放军第四军医大学军事预防医学系放射医学教研室实验室完成。材料：8～10周龄、清洁级雄性BALB／C小鼠132只；磁场装置采用HMF-6000旋转磁场治疗装置（中国专利号ZL9311801．1，美国发明号为5．667．469）。方法：132只小鼠随机分为正常组，单纯磁疗组，单纯照射组和照射磁疗组4组，单纯照射组和照射磁疗组小鼠接受吸收剂量6．0Gy的^60Coγ射线全身一次照射，其他2组不予以照射；照射当天开始单纯磁疗组及照射磁疗组予以磁场处理30d，2次/d，1．5h/次。主要观察指标：分别于照射后第9，23，30天测定小鼠血清超氧化物歧化酶活力，丙二醛浓度。结果：72只小鼠进入结果分析。①磁疗后第9天，照射磁疗组超氧化物歧化酶活力高于单纯照射组，丙二醛浓度低于单纯照射组（P〈0．05）。②磁疗后第23天，照射磁疗组的丙二醛浓度低于单纯照射组（P〈0．05），两组均高于单纯磁疗组及正常组（P〈0．05）。③单纯磁疗组与正常组比较，3个时间点的超氧化物歧化酶活力及丙二醛浓度均无显著差异（P〉0．05）。结论：①旋转磁场对放射损伤小鼠的自由基有一定影响，早期具有增强超氧化物歧化酶活力、降低丙二醛浓度的作用。②磁场暴露对正常小鼠自由基未产生明显影响。

BACKGROUND： It has been proven that magnetic field can increase the survival rate and duration of mice with irradiation-caused injury. It implied that the magnetic field could affect the free radicals of the radiation-injured mice. OBJECTIVE： To explore the effect of rotation magnetic field on the activity of serum superoxide dismutase （SOD） and the content of malondialdehyde （MDA） in radiation-injured mice. DESIGN, TIME AND SETTING： The randomized controlled animal trial was performed at the laboratory of Faculty of Preventive Medicine, Fourth Military Medical University of Chinese PLA from April to July 2007. MATERIALS： 132 adult clean-grade male BALB/C mice aging 8-10 weeks; HMF-6000 rotation magnetic field equipment （China patent： ZL9311801.1 ; American invention number： 5.667.469）. METHODS： 132 male BALB/C mice were randomly divided into normal group, magnetic treatment group, irradiation group and irradiation combining magnetic treatment group. Mice in the irradiation group and irradiation combining magnetic treatment group were exposed to irradiation with 6.0 Gy ^60CO γ rays, and the other groups received no irradiation. In addition, mice in the magnetic treatment group and irradiation combining magnetic treatment group were treated with a rotation magnetic field twice a day, 1.5 hours every time for 30 days since the day of irradiation. MAIN OUTCOME MEASURES： SOD activity and MDA content in serum were measured on days 9, 23 and 30 after irradiation. RESULTS： Seventy-two mice were included in final analysis. On the 9th day after magnetic field treatment, the SOD activity in serum of the irradiation combining magnetic treatment group was higher but MDA content was lower than that of the irradiation group （P 〈 0.05）. On the 23^rd day after magnetic field treatment, the MDA content in serum of the irradiation combining magnetic treatment group was lower than that of the irradiation group （P 〈 0.05）, and that of both irradiation combining magnetic treatment group and irradiation group was higher than that of magnetic treatment group and normal group （P 〈 0.05）. There were no statistical differences in SOD activity or MDA content between magnetic treatment group and normal group at the same time point （P 〉 0.05）. CONCLUSION： The rotation magnetic field could enhance SOD activity and decrease MDA content in the serum of radiation-injured mice. However, there are few changes in free radical production in the normal mice exposed to rotation magnetic field.