用水迷宫实验检测甲醛和乙苯联合染毒的神经毒性

目的探讨不同浓度甲醛和乙苯单独及联合染毒对小鼠神经行为的影响,分析其联合作用的类型。方法采用4×4析因设计,利用Morris水迷宫,研究甲醛(0、0.2、2.0、20.0mg/kg)、乙苯(0、50、250、500mg/kg),以及二者联合染毒对小鼠学习和记忆能力的影响。结果随着训练次数的增多,各组小鼠的逃避潜伏期呈下降趋势(P<0.05);逃避潜伏期随染毒剂量的增大而延长;染毒组的逃避潜伏期均长于阴性对照组(P<0.05),联合高剂量组的逃避潜伏期长于其他各组(P<0.05)。甲醛和乙苯单独及联合染毒均可导致小鼠第一次跨越原平台位置的时间延长(P<0.05),目标象限(Ⅳ象限)停留时间缩短(P<0.05),以及原平台象限游泳距离占总距离百分比下降(P<0.05);以上变化以联合高剂量染毒组小鼠最为突出。联合染毒对小鼠第一次跨越原平台位置的时间和原平台象限游泳距离占总距离百分比的影响存在交互作用(P<0.05)。结论甲醛和乙苯均可危害小鼠的学习和记忆能力,联合染毒组的危害程度大于单独染毒组,二者的联合效应表现为协同作用。

Morris water maze test for measurement of combined neurotoxicity induced by formaldehyde and ethyl ben zene in mice

Objective To explore the neurotoxicity of various concentrations of formaldehyde and ethyl benzene alone or in combination and to analyze the phenotypes of the combined neurotoxicity in mice. Methods The Morris water maze test was conducted, based on 4x4 factorial experiment design, to investigate the effects of various concen trations of formaldehyde （0, 0.2, 2.0 and 20.0 mg/kg） and ethyl benzene （0, 50, 250 and 500 mg/kg） or in combination on the capacity of learning and memory in mice. Resets Increased number of training resulted in shortened escape latent period, which was prolonged as the dose of exposure increased in all groups （P〈0.05）. The mice exposed to formaldehyde or ethyl benzene, particularly the high-dose exposure group （P〈0.05）, yielded a prolonged escape latency period than the negative control group （P〈0.05）. Exposure to either or combined agents, particularly the high-dose ex- posure group, led to prolonged duration of crossing the platform initially, shortened duration of stay and reduced per- centage of swimming distance to the total distance in the target （the 4th） quadrant （all P〈0.05）. An interaction was found in the effects of combined exposure on the initial duration of crossing the platform and the percentage of swim- ming distance to the total distance in the target quadrant （P〈0.05）. Conclusion Formaldehyde and ethyl benzene are hazardous to learning and memory in mice, as evidenced by the fact that combined exposure is associated with in- creased and synergistic toxicity compared with single exposure.