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Sakamaki Y, Shobudani M, Ojiro R, Ozawa S, Tang Q, Zou X, Ebizuka Y, Karasawa A, Woo G, Yoshida T, Shibutani M. Suppression of Hippocampal Neurogenesis and Oligodendrocyte Maturation Similar to Developmental Hypothyroidism by Maternal Exposure of Rats to Ammonium Perchlorate, a Gunpowder Raw Material and Known Environmental Contaminant. ENVIRONMENTAL TOXICOLOGY 2025; 40:30-53. [PMID: 39248596 PMCID: PMC11628657 DOI: 10.1002/tox.24413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 07/18/2024] [Accepted: 08/17/2024] [Indexed: 09/10/2024]
Abstract
The environmental contaminant perchlorate raises concern for hypothyroidism-related brain disorders in children. This study investigated the effects of developmental perchlorate exposure on hippocampal neurogenesis and oligodendrocyte (OL) development. Pregnant Sprague-Dawley rats were administered with ammonium perchlorate (AP) in drinking water at concentrations of 0 (control), 300, and 1000 ppm from gestation day 6 until weaning [postnatal day (PND) 21]. On PND 21, offspring displayed decreased serum triiodothyronine and thyroxine concentrations at 1000 ppm and thyroid follicular epithelial cell hyperplasia at ≥300 ppm (accompanying increased proliferation activity at 1000 ppm). Hippocampal neurogenesis indicated suppressed proliferation of neurogenic cells at ≥300 ppm, causing decreases in type-1 neural stem cells (NSCs) and type-2a neural progenitor cells. In addition, an increase of SST+ GABAergic interneurons and decreasing trend for ARC+ granule cells were observed at 1000 ppm. CNPase+ mature OLs were decreased in number in the dentate gyrus hilus at ≥300 ppm. At PND 77, thyroid changes had disappeared; however, the decrease of type-1 NSCs and increase of SST+ interneurons persisted, CCK+ interneurons were increased, and white matter tissue area was decreased at 1000 ppm. Obtained results suggest an induction of hypothyroidism causing suppressed hippocampal neurogenesis (targeting early neurogenic processes and decreased synaptic plasticity of granule cells involving ameliorative interneuron responses) and suppressed OL maturation during the weaning period. In adulthood, suppression of neurogenesis continued, and white matter hypoplasia was evident. Observed brain changes were similar to those caused by developmental hypothyroidism, suggesting that AP-induced developmental neurotoxicity was due to hypothyroidism.
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Affiliation(s)
- Yuri Sakamaki
- Laboratory of Veterinary Pathology, Division of Animal Life Science, Institute of AgricultureTokyo University of Agriculture and TechnologyTokyoJapan
| | - Momoka Shobudani
- Laboratory of Veterinary Pathology, Division of Animal Life Science, Institute of AgricultureTokyo University of Agriculture and TechnologyTokyoJapan
| | - Ryota Ojiro
- Laboratory of Veterinary Pathology, Division of Animal Life Science, Institute of AgricultureTokyo University of Agriculture and TechnologyTokyoJapan
- Cooperative Division of Veterinary Sciences, Graduate School of AgricultureTokyo University of Agriculture and TechnologyTokyoJapan
| | - Shunsuke Ozawa
- Laboratory of Veterinary Pathology, Division of Animal Life Science, Institute of AgricultureTokyo University of Agriculture and TechnologyTokyoJapan
- Cooperative Division of Veterinary Sciences, Graduate School of AgricultureTokyo University of Agriculture and TechnologyTokyoJapan
| | - Qian Tang
- Laboratory of Veterinary Pathology, Division of Animal Life Science, Institute of AgricultureTokyo University of Agriculture and TechnologyTokyoJapan
- Cooperative Division of Veterinary Sciences, Graduate School of AgricultureTokyo University of Agriculture and TechnologyTokyoJapan
| | - Xinyu Zou
- Laboratory of Veterinary Pathology, Division of Animal Life Science, Institute of AgricultureTokyo University of Agriculture and TechnologyTokyoJapan
- Cooperative Division of Veterinary Sciences, Graduate School of AgricultureTokyo University of Agriculture and TechnologyTokyoJapan
| | - Yuri Ebizuka
- Laboratory of Veterinary Pathology, Division of Animal Life Science, Institute of AgricultureTokyo University of Agriculture and TechnologyTokyoJapan
| | - Ayumi Karasawa
- Laboratory of Veterinary Pathology, Division of Animal Life Science, Institute of AgricultureTokyo University of Agriculture and TechnologyTokyoJapan
| | - Gye‐Hyeong Woo
- Laboratory of Histopathology, Department of Clinical Laboratory ScienceSemyung UniversityJecheonChungbukRepublic of Korea
| | - Toshinori Yoshida
- Laboratory of Veterinary Pathology, Division of Animal Life Science, Institute of AgricultureTokyo University of Agriculture and TechnologyTokyoJapan
- Cooperative Division of Veterinary Sciences, Graduate School of AgricultureTokyo University of Agriculture and TechnologyTokyoJapan
| | - Makoto Shibutani
- Laboratory of Veterinary Pathology, Division of Animal Life Science, Institute of AgricultureTokyo University of Agriculture and TechnologyTokyoJapan
- Cooperative Division of Veterinary Sciences, Graduate School of AgricultureTokyo University of Agriculture and TechnologyTokyoJapan
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Yu G, Wu L, Su Q, Ji X, Zhou J, Wu S, Tang Y, Li H. Neurotoxic effects of heavy metal pollutants in the environment: Focusing on epigenetic mechanisms. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 345:123563. [PMID: 38355086 DOI: 10.1016/j.envpol.2024.123563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 02/04/2024] [Accepted: 02/11/2024] [Indexed: 02/16/2024]
Abstract
The pollution of heavy metals (HMs) in the environment is a significant global environmental issue, characterized by its extensive distribution, severe contamination, and profound ecological impacts. Excessive exposure to heavy metal pollutants can damage the nervous system. However, the mechanisms underlying the neurotoxicity of most heavy metals are not completely understood. Epigenetics is defined as a heritable change in gene function that can influence gene and subsequent protein expression levels without altering the DNA sequence. Growing evidence indicates that heavy metals can induce neurotoxic effects by triggering epigenetic changes and disrupting the epigenome. Compared with genetic changes, epigenetic alterations are more easily reversible. Epigenetic reprogramming techniques, drugs, and certain nutrients targeting specific epigenetic mechanisms involved in gene expression regulation are emerging as potential preventive or therapeutic tools for diseases. Therefore, this review provides a comprehensive overview of epigenetic modifications encompassing DNA/RNA methylation, histone modifications, and non-coding RNAs in the nervous system, elucidating their association with various heavy metal exposures. These primarily include manganese (Mn), mercury (Hg), lead (Pb), cobalt (Co), cadmium (Cd), nickel (Ni), sliver (Ag), toxic metalloids arsenic (As), and etc. The potential epigenetic mechanisms in the etiology, precision prevention, and target therapy of various neurodevelopmental disorders or different neurodegenerative diseases are emphasized. In addition, the current gaps in research and future areas of study are discussed. From a perspective on epigenetics, this review offers novel insights for prevention and treatment of neurotoxicity induced by heavy metal pollutants.
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Affiliation(s)
- Guangxia Yu
- Key Lab of Environment and Health, School of Public Health, Fujian Medical University, Fuzhou 350122, China; Department of Preventive Medicine, School of Public Health, Fujian Medical University, Fuzhou 350122, China
| | - Lingyan Wu
- Key Lab of Environment and Health, School of Public Health, Fujian Medical University, Fuzhou 350122, China
| | - Qianqian Su
- Key Lab of Environment and Health, School of Public Health, Fujian Medical University, Fuzhou 350122, China
| | - Xianqi Ji
- Key Lab of Environment and Health, School of Public Health, Fujian Medical University, Fuzhou 350122, China
| | - Jinfu Zhou
- Key Lab of Environment and Health, School of Public Health, Fujian Medical University, Fuzhou 350122, China; Fujian Maternity and Child Hospital College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, Fuzhou 350001, China
| | - Siying Wu
- Key Lab of Environment and Health, School of Public Health, Fujian Medical University, Fuzhou 350122, China; Department of Epidemiology and Health Statistics, School of Public Health, Fujian Medical University, Fuzhou 350122, China
| | - Ying Tang
- Fujian Center for Prevention and Control Occupational Diseases and Chemical Poisoning, Fuzhou 350125, China
| | - Huangyuan Li
- Key Lab of Environment and Health, School of Public Health, Fujian Medical University, Fuzhou 350122, China; Department of Preventive Medicine, School of Public Health, Fujian Medical University, Fuzhou 350122, China.
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