不同条件微波辐射致大鼠学习和记忆能力及脑组织结构改变的影响研究

摘要

目的 探讨微波单次和累积辐射对大鼠学习和记忆能力以及脑组织结构的影响.方法 对80只二级SD大鼠采用单次和累积辐射,单次辐射平均功率密度分别为2 mW/cm2和11 mW/cm2,累积辐射组每天辐射,平均功率密度为4.68 μW/ cm2,连续辐射30 d.采用Morris水迷宫观察大鼠学习与记忆能力的改变,于辐射后1,7,14,30,60 d采用光镜和电镜观察大鼠脑组织学和超微结构的改变.结果 (1)单次辐射后,与正常对照组相比,各辐射组大鼠逃避潜伏期均在辐射后有不同程度延长.2 mW/cm2组辐射后1 d和2 d,大鼠逃避潜伏期差异有显著性,11 mW/cm2组辐射后1 d和3 d,逃避潜伏期有显著性差异.累积辐射后大鼠逃避潜伏期无显著性差异.(2)11 mW/cm2组辐射后7～14 d,大鼠海马和大脑皮质神经元皱缩,核固缩,线粒体肿胀,局部空化,内质网扩张,突触间隙不清、囊泡减少,血管内皮连接增宽;累积辐射后14 d,大鼠海马及大脑皮质神经元固缩,线粒体肿胀空化,内质网扩张,突触间隙不清.结论 2和11 mW/cm2微波单次辐射可使大鼠学习和记忆能力下降,大鼠脑组织结构损伤; 4.68 μW/cm2 30 d微波累积辐射可引起大鼠脑组织结构损伤.%Objective To investigate the effect on abilities of learning and memory and the structural changes of the brain in rats induced by acute and long-term microwave radiation. Methods Eighty male SD rats were exposed to acute microwave radiation for 10 s or long-term microwave radiation for 12 h per day over a period of 30 d. The mean power densities of single radiation was 2 mW/cm2 and 11 mW/cm2 . and that of long-term radiation was 4. 68 μW/cm2 . The learning and memory ahilities of rats were tested hy Morris water maze. The morphological changes in brain tissues were observed on dd 1, 7. 14 , 30 , 60 after radiation by light and electron microscopy. Results ( 1 ) After acute radiation, the average escape latency ( AEL ) of rats in radiation groups was longer than in sham treated group and was significantly different in the 2 mW/cm2 group on day 1 and 2 and in the 11 mW/cm2 group on dd 1 and 3. The long-term radiation group was similar to the sham-treated group. ( 2 ) On d 7 to d 14 after 11 mW/cm2 acute microwave radiation,the crenation and pycnosis were seen in hippocampus and cortical neurons. The ultrastructure of neurons showed that mitochondria swelled and became vacuolated, endoplasmic reticulum was dilated, synaptic clefts blurred, synapse vesicles decreased and endothelium connection of the blood vessel widened. On d 14 after long-term radiation, pycnosis was seen in hippocampus and cortical neurons. The ultrastructure of neurons showed mitochondrial swelling and vacuolation, endoplasmic reticulum dilation and blurred synaptic clefts. Conclusion Acute microwave radiation ( 2 - 11 mW/cm2 ) can result in the decline of the learning and memory abilities and morphologic injury of the brain in rats. Long-term microwave radiation ( 4. 68 μW/ cm2 ) for one month can result in morphologic injury to the brain.