甲醛对小鼠记忆力及脑组织神经递质水平的影响

研究甲醛暴露小鼠记忆力和脑组织神经递质含量的变化情况，探讨甲醛对小鼠的中枢神经系统毒性及其作用机制。方法：选择健康昆明小鼠48只，随机分为4组，即对照组和低剂量（1/24 LC50，21.0 mg/m³）、中剂量(1/12 LC50，42.0 mg/m³)、高剂量(1/6 LC50，84.0 mg/m³)染毒组，每组12只。染毒组小鼠吸入既定浓度的甲醛，采用静式吸入染毒，每天2 h，每周 6 d，染毒12周；对照组通以室外洁净空气。染毒第6、8、12周的第1天，进行小鼠记忆力的测试。染毒结束后处死小鼠，测定脑组织匀浆中一氧化氮（NO）、乙酰胆碱（Ach）和谷氨酸（Glu）含量。结果：在水迷宫试验中，第8周，高剂量染毒组小鼠游泳到达目的地的时间大于对照组（P<0.05）；第12周，中剂量和高剂量染毒组小鼠游泳到达目的地的时间大于对照组（P<0.01），高剂量染毒组小鼠到达目的地的时间也大于低剂量组（P<0.01），高剂量染毒组小鼠游泳到达目的地的时间大于其第8周所用时间（P<0.01）。染毒组小鼠脑组织Ach含量明显低于对照组(P<0.01)，Glu含量明显高于对照组(P<0.01)，各组小鼠脑组织NO含量比较差异无统计学意义（P>0.05）。结论：小鼠较长时间接触甲醛可引起记忆力的降低，并可引起脑组织神经递质Ach含量的下降及Glu含量的升高，提示脑神经递质含量的改变可能是小鼠记忆力降低的机制之一。

Effects of formaldehyde on memory and content of neurotransmitter in cerebral tissue of mice

Objective To study the effects of formaldehyde on memory and the content of neurotransmitter in the cerebral tissue of mice,and explore the effects of formaldehyde on central nervous system and its possible mechanism.Methods 48 Kunming mice were randomly divided into 4 groups:negative control,three experiment groups(low dose group:1/24 LC50,21.0 mg·m-3;middle dose group: 1/12 LC50,42.0 mg·m-3;and high dose group:1/6 LC50,84.0 mg·m-3).The mice in experiment groups were exposed to formaldehyd by inspiration in a static total enclosure chamber for 12 weeks.At the first day of the 6th week,8th week and 12th week,the memory of mice was determined,and the neurotransmitters in the cerebral tissue were determined at the end of exposure to toxicants.Results In water maze test,at the 8th week,the swimming time of achieving the goal of the mice in high dose group was longer than that in control group(P<0.05).At the 12th week,the swimming time of achieving the goal of the mice in middle dose group and high dose group was increased compared with control group(P<0.01).And the swimming time of achieving the goal of the mice in high dose group increased compared with low dose group.(P<0.01).In high dose group,the swimming time of achieving the goal at the 12th week was increased compared with the 8th week(P<0.01).The contents of Ach in cerebral tissue in experiment groups were lower than that in control group(P<0.01),and the contents of Glu in cerebral tissue were higher than that in control group(P<0.01).The content of NO in cerebral tissue of mice in each group had no significant difference(P>0.05).Conclusion Long-term exposure to formaldehyde can cause the decreasing of memory,decreasing of the content of Ach and increasing of the content of Glu in the cerebral tissue.It indicates that the change of neurotransmitter contents may be one of mechanisms of decreasing of memory in mice.