X射线对仔鼠大脑枕叶皮层结构及大脑超氧化物歧化酶、过氧化氢酶活性及丙二醛含量的影响

目的观察X射线辐射后仔鼠大脑枕叶皮层结构、大脑重量及大脑中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性和丙二醛(MDA)含量的动态变化,探讨X射线辐射对仔鼠大脑发育的影响。方法对160只仔鼠(出生6～7d)用不同吸收剂量(0Gy、1Gy、3Gy、5Gy和7Gy)X射线进行全身辐射,分别于辐射后1d、5d、10d和20d,用比色法检测仔鼠大脑中SOD、CAT活性及MDA含量的变化,称量检测各期仔鼠大脑重量的变化,用显微技术观察仔鼠大脑枕叶皮层结构的变化。结果 X射线辐射影响仔鼠大脑的生长发育,辐射后1～20d,除1Gy辐射组在1～10d时仔鼠大脑重量高于对照组,其他辐射组仔鼠大脑重量均低于对照组,差异显著或极显著(P0.05或P0.01);1Gy辐射组在5～20d时,仔鼠大脑中SOD和CAT活性高于对照组,差异显著(P0.05),MDA含量低于对照组,差异显著或极显著(P0.05或P0.01);3Gy辐射组仔鼠大脑中SOD、CAT活性先降低后又逐渐升高,但仍低于对照组,MDA含量先升高后降低,但仍高于对照组;5Gy、7Gy辐射组仔鼠大脑中SOD、CAT活性明显低于对照组,差异极显著(P0.01),MDA含量明显高于对照组,差异极显著(P0.01);辐射组仔鼠大脑枕叶皮层厚度减小,皮层结构不清,除1Gy辐射组在1d时仔鼠大脑枕叶皮层第II、III、VI层的细胞面密度值高于对照组及在20d时第III、V、VI层的细胞面密度值高于对照组,其他辐射组仔鼠大脑枕叶皮层各层细胞密度值均低于对照组。结论 X射线辐射影响仔鼠大脑的重量和皮层组织结构,这可能与大脑中抗氧化酶活性降低和MDA含量升高有一定的关系。

Effects of X-ray on structure of cerebral occipital lobe cortex and activities of superoxide dismutase, catalase and content of malonaldehyde in cerebrum of filial mice

Objective To investigate the dynamic changes of structure of cerebral occipital lobe cortex and cerebral weight and activities of superoxide dismutase(SOD),catalase(CAT) and content of malonaldehyde(MDA) after irradiation with different dosages of X-ray in filial mice,and to explore effects of X-ray on cerebral development of filial mice. Methods One hundred and sixty filial mice（birth 6-7 days）were irradiated with different dosages (0Gy,1Gy,3Gy,5Gy,7Gy) of X-ray ,At 1day, 5days, 10days and 20days after irradiation,cerebral weight of filial mice was weighted. And it was observed that the changes of the structure of the cerebral occipital lobe cortex of filial mice by biomicroscopy and detected the activities of SOD, CAT and content of MDA by colorimetry from all irradiated groups of different stages. Results X-ray affected the development of cerebrum in filial mice , at 1 day-20 days after irradiated,cerebral weight of other irradiated groups was lighter than that of the control group except 1Gy irradiated group(EM>P/EM><0.05 or EM>P/EM><0.01);SOD and CAT activities increased and MDA content decreased in 1Gy group at 5-20 days after irradiation; In 3Gy group,SOD and CAT activities decreased firstly and then increased slowly, but it was always lower than those of control group and MDA content increased in the early time, then decreased, but it was always higher than that of the control group; SOD and CAT activities in 5Gy,7Gy group filial mice were significantly lower than that of the control group(EM>P/EM><0.01), and MDA content significantly was higher than that of the control group(EM>P/EM><0.01);The thickness of cerebral occipital lobe cortex in irradiated groups decreased, structure of cerebral occipital lobe cortex was not clear, the number of neurons was lower than that of the control group except those in cerebral occipital lobe cortex II,III,VI at one day and those in cerebral occipital lobe cortex III,V,VI at 20 days after irradiation in 1Gy group filial mice. Conclusion X-ray radiation affects the cerebral weight and the structure of filial mouse cerebrum, this effect might be correlated with the high activities of SOD, CAT and low content of MDA in filial mouse brain.