| IntroductionArsenic has toxic effects on the body of the multiple organs and systems. Recent epidemiological survey showed that environmental arsenic exposure can affect children's intellectual development. Hippocampus which mainly constituted by glial cells and neurons is considered as an important part about learning and memory. Astrocytes(AS) is a major component of glial cells, accounting for about 70%. Glial fibrillary acidic protein (GFAP) that only exists in astrocytes is a recognized characteristic astrocyte marker. S-100βis also a specific AS marker. It's level may reflect the extent of brain damage and is a sign of AS activation. Nissl body is a kind of basophilic material within the cytoplasm, the main function of Nissl body is synthesing protein. Nissl body closely related to the function of neurons and can be used as status flags of neurons.In this study, I detected the arsenic forms and levels of various arsenic forms in the brains and blood of mice. I also choosed GFAP and S-100βas the functional targets of AS, Nissl body as the target of neurons by toluidine blue staining to investigate the effects of arsenic exposure on AS and neurons.Materials and Methods56 Kunming mice were randomly divided into four groups, which were control group, low dose group, medium dose group and high dose group. Mice were exposed to arsenite through drinking water for 42 days. After that choosed 8 mice from each group and detected the blood and brains of the mice by atomic absorption spectrophotometer. Expression of GFAP and S100βprotein and Nissl body in hippocampal CA1, CA3 and DG of the rest mice were determined by immunohistochemistry stain and toluidine blue stain method.Results1. Disposition of arsenic in the blood and brain of miceIn the blood of mice, the level of iAs, MMA, DMA, and TAs were all increased along with the arsenic dose. In the brain of mice, the level of iAs, MMA, DMA, and TAs were also increased along with the arsenic dose except 25mg/L arsenic exposure groups.2. Influence of arsenic exposure on expression of GFAP in hippocampal AS of miceIn hippocampal CA1 and DG of male mice the integral optical density (IOD) of GFAP was increased and then decreased along with the arsenic dose; IOD in medium dose group was the highest and significantly higher than that in control; however, IOD of GFAP in CA3 of male mice was increased along with arsenic dose, which was the highest in high dose group and significantly higher than that in control. In hippocampal CA1, CA3 and DG of female mice, IOD of GFAP was increased and then decreased along with the arsenic dose; IOD in CA1 and DG of low dose group was the highest and significantly higher that than in control, but was significantly lower in high dose group than that in control; however, IOD in CA3 of medium dose group was the highest, and was significantly higher in both low and medium dose group than that in control, but was significantly lower in high dose group than that in control.3. Influence of arsenic exposure on expression of S100βin hippocampal AS of miceIn hippocampal CA1 and DG of male mice, the IOD of S100βwas increased and then decreased along with the arsenic dose; IOD in CA1 of low dose group was the highest, but was significantly lower in medium dose group and high dose group than that in control;however, IOD in DG of medium dose group was the highest, and was significantly higher in both low and medium dose group than that in control;IOD of S100βin CA3 of male mice was increased along with arsenic dose, which was the highest in high dose group and significantly higher than that in control. In hippocampal CA1, CA3 and DG of female mice, the IOD of S100βwas decreased along with the arsenic dose; IOD that in all three dose groups ignificantly lower than that in control,and, was the lowest in high dose group.4. Influence of arsenic exposure on Nissl body in hippocampal neurons of miceIn hippocampal CA1, DG of mice, the IOD of Nissl body was increased and then decreased along with the arsenic dose; IOD in CA1 and DG of medium dose group was the highest and significantly higher that than in control, however was significantly lower in high dose group than that in control; IOD of Nissl body in CA3 of mice was increased along with arsenic dose, which was the highest in high dose group and significantly higher than that in control.Conclusion1. Exposure to low arsenic levels could activate AS, however high levels of arsenic could injure AS.2. Compared to male mice, AS in hippocampus of female mice are more sensitive to the effects of arsenic. Effects of arsenic on AS in CA1 and DG seemed to be more stronger than in CA3.3. S-100βis more sensitive than GFAP to arsenic exposuring.4. The influence of arsenic exposure on neuron is familiar to AS in hippocampal of mice.
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