Abstract: 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.

Key words: X-ray, Cerebral occipital lobe, Superoxide dismutase, Catalase, Malonaldehyde, Colorimetry, Filial mouse