Toxicological Research

Korean Society of Toxicology & Korea Environmental Mutagen Society (한국독성학회)
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Neurobehavioral effects of the exposure to mercury vapor and methylmercury during postnatal period on mice

  • Jin‑Yong Lee (Laboratory of Pharmaceutical Health Sciences, School of Pharmacy, Aichi Gakuin University) ;
  • Minoru Yoshida (Department of Nursing, Tokyo Junshin University) ;
  • Masahiko Satoh (Laboratory of Pharmaceutical Health Sciences, School of Pharmacy, Aichi Gakuin University) ;
  • Chiho Watanabe (Interfaculty Initiative in Planetary Health, Nagasaki University)
  • Received : 2023.02.08
  • Accepted : 2023.08.24
  • Published : 2024.01.15
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Abstract

In this study, we investigated the neurobehavioral alterations and modifications of gene expression in the brains of female mice exposed to low-level mercury vapor and/or methylmercury during postnatal development. The mice were exposed to low-level mercury vapor at a mean concentration of 0.094 mg/m3 and supplied with tap water containing 5 ppm methylmercury from postnatal day 11 to 12 weeks of age. Behavioral analyses were performed at 17 weeks of age. Total locomotor activity in the open field test and the retention trial performance in the passive avoidance test were significantly reduced in the combined exposure group compared with those in the control group. The differences in locomotor activity and performance in the retention trial at 17 weeks were no longer detected at 45 weeks. These results suggest that the effect of aging on the behavioral abnormalities resulting from postnatal exposure to mercury complexes are not significant. In the microarray analysis of brains in the combined exposure group, the gene expression levels of Ano2 and Sgk1 were decreased. Real-time RT-PCR analysis confirmed these changes caused by combined mercury exposure, showing significant downregulation of Ano2 and Sgk1 in the cerebrum. These genes play key roles in the brain as a calcium-activated chloride channel and as a kinase that responds to cellular stress, respectively. Our findings provide insight into the neurobehavioral changes caused by combined mercury exposure.

Keywords

Acknowledgement

This research was funded by Ministry of Education, Culture, Sports, Science and Technology, Japan (Grant in Aid for Scientific Research [C], No. 18K10029).

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