| Project/Area Number |
16590488
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Hygiene
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| Research Institution | St.Marianna University School of Medicine |
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Principal Investigator |
YOSHIDA Minoru St.Marianna University School of Medicine, Associate Professor, 医学部, 助教授 (80081660)
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| Co-Investigator(Kenkyū-buntansha) |
SATOH Masahiko Gifu Pharmaceutical University, Associate Professor, 薬学部, 助教授 (20256390)
WATANABE Chiho The University of Tokyo, Professor, 大学院・医学系研究科, 教授 (70220902)
TADOKORO Mamoru St.Marianna University School of Medicine, Professor, 医学部, 教授 (80081644)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2005: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2004: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | exposure to mercury vapor / neurobehavioral changes / neonate / fetus / metallothionein (MT) / DNA microarray / mice / MT-null mice / メタロチオネイン / 胎生期 / 水銀 / メタロチオネイン欠損 |
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| Research Abstract |
We studied the neurobehavioral effects of prenatal and postnatal exposure of MT-null and wild-type mice to elemental mercury vapor (Hg^0). Pregnant mice of both strains were repeatedly exposed to Hg^0 vapor at 0.50 and 0.56 mg/m^3 for 6 h per day until the 18th day of gestation. The behavioral effects were evaluated with locomotor activity in the open field (OFT), learning ability in the passive avoidance response (PA) and spatial learning ability in the Morris water maze at 12 weeks of age. Hg^0-exposed MT-null mice showed a significant decrease in total locomotor activity in males, and a learning disability in the passive avoidance response and a retarded acquisition in the Morris water maze in females as compared with the control. In contrast, Hg^0-exposed wild-type mice did not differ from controls in three behavioral measurements.
Next, we studied the neurobehavioral effects of postnatal exposure of MT-null and wild-type mice to elemental mercury vapor (Hg^0). After parturition, the dam and neonates were exposed to Hg^0 vapor at 0.023 and 0.043 mg/m^3 for 6 h per day until weanling and the behavioral effects of evaluation was carried out at 12weeks of age. In OFT, Hg^0-exposed MT-null mice showed a significant decrease in total locomotor activity in females. However, the learning ability in the PA test and spatial learning ability was not affected the exposed mice of both strains. The results indicate that MT-null mice in females would be more susceptible than wild-type mice to the behavioral neurotoxicity of prenatal and postnatal Hg^0 exposure. Mercury concentrations in the brain of both strains in females were slightly higher in the exposed group than in the control group, indicating the retention of residual mercury even 12 weeks after the cessation of the exposure. From these results, we suggest that the increased susceptibility of MT-null females to behavioral changes caused by prenatal and postnatal Hg^0 exposure.
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