Neurobehavioral changes in metallothionein-null and wild-type mice by prenatal co-exposure prenatally exposed to mercury vapor.

我们研究了MT基因敲除小鼠和野生型小鼠产前同时暴露于元素汞蒸气（Hg^0）和甲基汞（MeHg）对神经行为的影响。两种品系孕鼠共暴露4组：Hg^0组以0.03mg/m^3的剂量每天暴露6 h，直至孕18天。甲基汞组在妊娠期至产后10 d内给予含5 μg/g甲基汞的饲料。共暴露组接受如上所述的MeHg和Hg^0蒸气的组合。12周后，以旷场自发活动（OPF）、被动回避反应（PA）和Morris水迷宫空间学习能力为指标，评价各组大鼠的行为学效应。在野生型小鼠中，虽然雄性和雌性的对照组与甲基汞组或共暴露组之间的运动距离（cm）存在显著差异，但雄性和雌性的对照组与Hg ^0组之间没有差异。 ...更多信息 观察到。另一方面，雄性MT基因敲除小鼠的自发活动水平在对照组与甲基汞组、汞组和联合暴露组之间没有显著差异。而在MT基因敲除的雌性小鼠中，对照组与Hg^0组和联合暴露组之间观察到显著差异。在被动回避任务的保持试验中，雄性和雌性的对照组与甲基汞组、汞组和混合暴露组的回避潜伏期无差异。在连续5天的Morris水迷宫实验中，甲基汞染毒组雄性小鼠在第4天和第5天的逃避时间显著长于对照组，联合染毒组仅在第4天的逃避时间显著长于对照组，而雌性小鼠在对照组和3个染毒组之间的逃避时间无显著性差异。相反，与对照组相比，MT基因敲除小鼠中的Hg^0组和共暴露组雌性小鼠在Morris水迷宫中的获得延迟。在该实验条件下，产前暴露于共同暴露的MT-null和野生型小鼠的神经行为变化似乎受到野生型小鼠中MeHg暴露和MT-null小鼠中Hg^0暴露的强烈影响。根据这些结果，我们认为MT基因敲除小鼠比野生型小鼠更容易受到产前汞暴露的行为神经毒性的影响。另一方面，野生型小鼠被证明比MT缺失小鼠更容易受到产前甲基汞暴露的行为神经毒性的影响。

We studied the neurobehavioral effects prenatal co-exposure of MT-null and wild-type mice to elemental mercury vapor (Hg^0) and methylmercury (MeHg). Four groups of pregnant mice of both strains were exposed as follows : Hg^0 group was repeatedly exposed to Hg^0 vapor at 0.03 mg/m^3 for 6h/day until the 18th day of gestation. MeHg group received diet containing 5 μg/g of MeHg during gestational periods and until 10 days after the delivery. Co-exposure group received a combination of MeHg and Hg^0 vapor as described above. The behavioral effects were evaluated with locomotor activity in the open field (OPF), learning ability in the passive avoidance response (PA) and spatial learning ability in the Morris water maze as 12 weeks. In the wild-type mice, although there is significant different in the locomotion distance (cm) among the control group and the MeHg group or the co-exposure group in males and females, no difference between the control group and the Hg^0 group in males and femal … More es was observed. On the other hand, there is no significant difference in the locomotor activity levels among the control group and the MeHg group, the Hg^0 group and the co-exposure group in the MT-null mice of males. In the MT-null mice of females, however, significant difference was observed among the control group and the Hg^0 group and the co-exposure group. In the retention trails in the passive avoidance task, there is no difference in avoidance latency among the control group and the MeHg group, the Hg^0 group and the co-exposure group in both strains of males and females. In the Morris water maze test for five consecutive days, the escape time in males of wild-type mice was significantly longer for the MeHg group in day 4 and day 5 and for the co-exposure group only in the day 4 than the control group, but there were no significant differences in the escape time among the control group and three exposed groups in the females. In contrast, the Hg^0 group and the co-exposure group in the MT-null mice showed a retarded acquisition in the Morris water maze in females as compared with the control group. Neurobehavioral changes in MT-null and wild-type mice prenatally exposed to the co-exposure appeared strongly influence by the MeHg exposure in the wild-type mice and the Hg^0 exposure in the MT-null mice under this experiment condition. From these results, we suggest that MT-null mice would be more susceptible than wild-type mice to the behavioral neurotoxicity of prenatal Hg^0 exposure. On the other hand, wild-type mice proved to be susceptible than MT-null mice to the behavioral neurotoxicity of prenatal MeHg exposure Less