Malyapa R S, Ahern E W, Bi C, Straube W L, LaRegina M, Pickard W F, Roti Roti J L
Radiation Oncology Center, Mallinckrodt Institute of Radiology, Washington University, St. Louis, Missouri 63108, USA.
Radiat Res. 1998 Jun;149(6):637-45.
The present study was done to confirm the reported observation that low-intensity acute exposure to 2450 MHz radiation causes DNA single-strand breaks (Lai and Singh, Bioelectromagnetics 16, 207-210, 1995). Male Sprague-Dawley rats weighing approximately 250 g were irradiated with 2450 MHz continuous-wave (CW) microwaves for 2 h at a specific absorption rate of 1.2 W/kg in a cylindrical waveguide system (Guy et al., Radio Sci. 14, 63-74, 1979). There was no associated rise in the core body temperature of the rats. After the irradiation or sham treatments, rats were euthanized by either CO2 asphyxia or decapitation by guillotine (eight pairs of animals per euthanasia group). After euthanasia the brains were removed and immediately immersed in cold Ames medium and the cells of the cerebral cortex and the hippocampus were dissociated separately and subjected to the alkaline comet assay. Irrespective of whether the rats were euthanized by CO2 asphyxia or decapitated by guillotine, no significant differences were observed between either the comet length or the normalized comet moment of cells from either the cerebral cortex or the hippocampus of sham-treated rats and those from the irradiated rats. However, the data for the rats asphyxiated with CO2 showed more intrinsic DNA damage and more experiment-to-experiment variation than did the data for rats euthanized by guillotine. Therefore, the guillotine method of euthanasia is the most appropriate in studies relating to DNA damage. Furthermore, we did not confirm the observation that DNA damage is produced in cells of the rat cerebral cortex or the hippocampus after a 2-h exposure to 2450 MHz CW microwaves or at 4 h after the exposure.
本研究旨在证实已报道的观察结果，即低强度急性暴露于2450 MHz辐射会导致DNA单链断裂（Lai和Singh，《生物电磁学》16卷，207 - 210页，1995年）。体重约250 g的雄性Sprague-Dawley大鼠在圆柱形波导系统中以1.2 W/kg的比吸收率接受2450 MHz连续波（CW）微波照射2小时（Guy等人，《无线电科学》14卷，63 - 74页，1979年）。大鼠的核心体温没有相应升高。照射或假处理后，通过二氧化碳窒息或断头台斩首对大鼠实施安乐死（每个安乐死组8对动物）。安乐死后，取出大脑并立即浸入冷的艾姆斯培养基中，分别分离大脑皮层和海马体的细胞，并进行碱性彗星试验。无论大鼠是通过二氧化碳窒息安乐死还是被断头台斩首，假处理大鼠和照射大鼠大脑皮层或海马体细胞的彗星长度或标准化彗星矩均未观察到显著差异。然而，与断头台斩首的大鼠数据相比，二氧化碳窒息大鼠的数据显示出更多的内源性DNA损伤和更多的实验间差异。因此，在与DNA损伤相关的研究中，断头台安乐死方法是最合适的。此外，我们没有证实以下观察结果：大鼠暴露于2450 MHz CW微波2小时后或暴露后4小时，其大脑皮层或海马体细胞会产生DNA损伤。
