重金属铬、铜、汞经不同途径神经毒性的对比研究

目的]探讨几种重金属通过不同的通路对小鼠行为学的影响。方法]昆明鼠经LashleyⅢH-W水迷宫筛选后,剔除学习记忆差的小鼠,通过慢性滴鼻给药和灌胃的途径,用水迷宫、洞板、自主活动箱测定小鼠给药前后行为学的改变,并利用同步辐射技术,观察小鼠脑部的形态学改变。对通过2种给药途径所造成的神经毒性进行对比研究,探讨重金属通过不同通路对机体所造成的毒性差异及其相关机制。结果]重铬酸钾滴鼻组用药前后洞板探索行为有明显变化（P〈0.05）,灌胃组给药前后无明显变化;几组重金属滴鼻给药组前后比较,神经系统的兴奋性有所增加,其中重铬酸钾滴鼻组和硫酸铜滴鼻组较为明显,灌胃组给药前后无明显变化;重铬酸钾滴鼻组小鼠和硫酸铜滴鼻组小鼠上台潜伏期有所增长,靶象限活动时间百分比、穿台次数减少,游泳速度有所减慢,灌胃组给药后潜伏期反有所缩短;HE染色和同步辐射观察显示,重铬酸钾滴鼻组小鼠海马部位神经元肿胀明显,空泡变性,可见胶质水肿,部分细胞坏死,并可见呈筛状的坏死灶,胞质中一些区域透光增加,灌胃组无明显改变。结论]这几种重金属离子在较低浓度时即可通过嗅觉通路沉积于脑,并能通过嗅觉途径改变小鼠的行为学,灌胃组在此浓度时对小鼠的行为学没有较大的改变,有些金属离子可以作为微量元素参与新陈代谢,对神经系统不造成损害。

The Relative Property Research about the Neurotoxic Effect of Heavy Metal Ion Copper,Mercury and Chrome to Mice through Olfactory Pathway and Lavage

Objective] To study the influence of certain heavy metal ions on the ability of learning and memory of kunming mice through olfactory pathway and alimentary canal. Method] The mice were screened by LashleyⅢH-W water maze, chronic nasal administration of heavy metal ion copper, mercury or chrome was carried out to the mice with normal ability of learning and memory. The neurobehavioral differences before and after heavy metal ions nasal administration and gavage administration were evaluated by water maze test, hole-board test, autonomic activities test. Mice chronic nasal administration of water and gavage administration of identical heavy metal ion were used as controls. Synchrotron radiation was employed to observe the morphology of the mice brains. Result] Hole-board test indicated chrome nasal administration group has obviously variation in exploratory behavior(P<0.05), lavage group and control group have no obviously variation(P>0.05); autonomic activities test indicated heavy metal ion administration groups have obviously increase in nervous excitation compared with control group, especially chrome and copper administration groups, lavage groups have no obviously variation(P>0.05); mouse water maze test(escape latency) indicated that chrome and copper administration groups' eclipse period increases, the ability of learning and memory was slow down compared with the blank control group, on the contrary lavage groups' eclipse period shorten; synchrotron radiation and HE indicated hippocampus neuron swelling and degeneration, necrosis. Conclusion] It approved that the heavy metal ion extreme low density can be absorbed through olfactory epithelium and enter in brain by axoplasmic transport and the heavy metal ion has its own effect on mice nervous system which change the mice ability of learning and memory and they can deposit in brain through olfactory pathway. However this level can't create neurotoxicity through digestive tract.