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Nagashima D, Zhang L, Kitamura Y, Ichihara S, Watanabe E, Zong C, Yamano Y, Sakurai T, Oikawa S, Ichihara G. Proteomic analysis of hippocampal proteins in acrylamide-exposed Wistar rats. Arch Toxicol 2019; 93:1993-2006. [DOI: 10.1007/s00204-019-02484-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 05/15/2019] [Indexed: 01/08/2023]
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Xu L, Qiu X, Wang S, Wang Q, Zhao XL. NMDA Receptor Antagonist MK801 Protects Against 1-Bromopropane-Induced Cognitive Dysfunction. Neurosci Bull 2018; 35:347-361. [PMID: 30569431 DOI: 10.1007/s12264-018-0321-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 09/27/2018] [Indexed: 12/22/2022] Open
Abstract
Occupational exposure to 1-bromopropane (1-BP) induces learning and memory deficits. However, no therapeutic strategies are currently available. Accumulating evidence has suggested that N-methyl-D-aspartate receptors (NMDARs) and neuroinflammation are involved in the cognitive impairments in neurodegenerative diseases. In this study we aimed to investigate whether the noncompetitive NMDAR antagonist MK801 protects against 1-BP-induced cognitive dysfunction. Male Wistar rats were administered with MK801 (0.1 mg/kg) prior to 1-BP intoxication (800 mg/kg). Their cognitive performance was evaluated by the Morris water maze test. The brains of rats were dissected for biochemical, neuropathological, and immunological analyses. We found that the spatial learning and memory were significantly impaired in the 1-BP group, and this was associated with neurodegeneration in both the hippocampus (especially CA1 and CA3) and cortex. Besides, the protein levels of phosphorylated NMDARs were increased after 1-BP exposure. MK801 ameliorated the 1-BP-induced cognitive impairments and degeneration of neurons in the hippocampus and cortex. Mechanistically, MK801 abrogated the 1-BP-induced disruption of excitatory and inhibitory amino-acid balance and NMDAR abnormalities. Subsequently, MK801 inhibited the microglial activation and release of pro-inflammatory cytokines in 1-BP-treated rats. Our findings, for the first time, revealed that MK801 protected against 1-BP-induced cognitive dysfunction by ameliorating NMDAR function and blocking microglial activation, which might provide a potential target for the treatment of 1-BP poisoning.
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Affiliation(s)
- Lin Xu
- School of Public Health, Shandong University, Jinan, 250012, China
| | - Xiaofei Qiu
- School of Public Health, Shandong University, Jinan, 250012, China
| | - Shuo Wang
- School of Pharmacy, Liaocheng University, Liaocheng, 252000, China
| | - Qingshan Wang
- School of Public Health, Dalian Medical University, Dalian, 116044, China.
| | - Xiu-Lan Zhao
- School of Public Health, Shandong University, Jinan, 250012, China.
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Zong C, Garner CE, Huang C, Zhang X, Zhang L, Chang J, Toyokuni S, Ito H, Kato M, Sakurai T, Ichihara S, Ichihara G. Preliminary characterization of a murine model for 1-bromopropane neurotoxicity: Role of cytochrome P450. Toxicol Lett 2016; 258:249-258. [DOI: 10.1016/j.toxlet.2016.07.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 06/13/2016] [Accepted: 07/10/2016] [Indexed: 11/27/2022]
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Huang F, Ichihara S, Yamada Y, Banu S, Ichihara G. Effect of 4-week inhalation exposure to 1-bromopropane on blood pressure in rats. J Appl Toxicol 2016; 37:331-338. [PMID: 27452781 DOI: 10.1002/jat.3364] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 06/18/2016] [Accepted: 06/18/2016] [Indexed: 01/12/2023]
Abstract
The pathophysiology of hypertension is complex and multifactorial, and includes exposure to various chemical substances. Several recent studies have documented the reproductive and neurological toxicities of 1-bromopropane (1-BP). Given that 1-BP increased reactive oxygen species in the brain of rats, we hypothesized that 1-BP also has cardiovascular toxicity through increased oxidative stress. To test this hypothesis, male F344 and Wistar Nagoya rats (n = 7-8 per group per test) were exposed to 0 or 1000 ppm of 1-BP via inhalation for 4 weeks (8 h per day, 7 days per week). The exposure to 1-BP increased systolic blood pressure. This effect was associated with a significant decrease in the reduced/oxidized glutathione ratio. A significant increase in nitrotyrosine levels, activation of the NADPH oxidase pathway, which was evidenced by upregulation of gp91phox, a NADPH oxidase subunit, and significant decreases in the expressions of antioxidant molecules such as Cu/Zn- and Mn-superoxide dismutase catalase, and nuclear factor erythroid 2-related factor 2, were observed in the aortas of Wistar Nagoya rats exposed to 1-BP. Our results indicate that subacute (4-week) inhalation exposure to 1-BP increases blood pressure and suggest that this cardiovascular toxic effect is due, at least in part, to increased oxidative stress mediated through activation of the NADPH oxidase pathway. Further study is needed to assess whether NADPH oxidase activation causes the increase in blood pressure in the rats exposed to 1-BP. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Fen Huang
- Department of Environmental and Occupational Health, Nagoya University Graduate School of Medicine, Nagoya, Japan.,School of Public Health, Anhui Medical University, Anhui, China
| | - Sahoko Ichihara
- Department of Human Functional Genomics, Life Science Research Center, Mie University, Tsu, Japan
| | - Yuki Yamada
- Department of Human Functional Genomics, Life Science Research Center, Mie University, Tsu, Japan.,Japanese Red Cross Wakayama Medical Center, Wakayama, Japan
| | - Shameema Banu
- Department of Environmental and Occupational Health, Nagoya University Graduate School of Medicine, Nagoya, Japan.,Department of Obstetrics and Gynecology, Shri Sathya Sai Medical College Hospital and Research Center, Tamil Nadu, India
| | - Gaku Ichihara
- Department of Environmental and Occupational Health, Nagoya University Graduate School of Medicine, Nagoya, Japan.,Department of Occupational and Environmental Health, Tokyo University of Science, Noda, Japan
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Huang Z, Ichihara S, Oikawa S, Chang J, Zhang L, Hu S, Huang H, Ichihara G. Hippocampal phosphoproteomics of F344 rats exposed to 1-bromopropane. Toxicol Appl Pharmacol 2015; 282:151-60. [PMID: 25448045 DOI: 10.1016/j.taap.2014.10.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 10/16/2014] [Accepted: 10/21/2014] [Indexed: 11/18/2022]
Abstract
1-Bromopropane (1-BP) is neurotoxic in both experimental animals and human. To identify phosphorylated modification on the unrecognized post-translational modifications of proteins and investigate their role in 1-BP-induced neurotoxicity, changes in hippocampal phosphoprotein expression levels were analyzed quantitatively in male F344 rats exposed to 1-BP inhalation at 0, 400, or 1000 ppm for 8 h/day for 1 or 4 weeks. Hippocampal protein extracts were analyzed qualitatively and quantitatively by Pro-Q Diamond gel staining and SYPRO Ruby staining coupled with two-dimensional difference in gel electrophoresis (2D-DIGE), respectively, as well as by matrix-assisted laser-desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) to identify phosphoproteins. Changes in selected proteins were further confirmed by Manganese II (Mn(2+))-Phos-tag SDS-polyacrylamide gel electrophoresis (SDS-PAGE). Bax and cytochrome c protein levels were determined by western blotting. Pro-Q Diamond gel staining combined with 2D-DIGE identified 26 phosphoprotein spots (p<0.05), and MALDI-TOF/MS identified 18 up-regulated proteins and 8 down-regulated proteins. These proteins are involved in the biological process of response to stimuli, metabolic processes, and apoptosis signaling. Changes in the expression of phosphorylated 14-3-3 θ were further confirmed by Mn(2+)-Phos-tag SDS-PAGE. Western blotting showed overexpression of Bax protein in the mitochondria with down-regulation in the cytoplasm, whereas cytochrome c expression was high in the cytoplasm but low in the mitochondria after 1-BP exposure. Our results suggest that the pathogenesis of 1-BP-induced hippocampal damage involves inhibition of antiapoptosis process. Phosphoproteins identified in this study can potentially serve as biomarkers for 1-BP-induced neurotoxicity.
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Affiliation(s)
- Zhenlie Huang
- Guangdong Provincial Key Laboratory of Occupational Disease Prevention and Treatment, Guangdong Province Hospital for Occupational Disease Prevention and Treatment, Guangzhou 510-300, PR China; Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Sahoko Ichihara
- Graduate School of Regional Innovation Studies, Mie University, Tsu 514-8507, Japan
| | - Shinji Oikawa
- Department of Environmental and Molecular Medicine, Mie University Graduate School of Medicine, Mie 514-8507, Japan
| | - Jie Chang
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan; Graduate School of Regional Innovation Studies, Mie University, Tsu 514-8507, Japan
| | - Lingyi Zhang
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan; Department of Occupational and Environmental Health, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Noda 278-8510, Japan
| | - Shijie Hu
- Guangdong Provincial Key Laboratory of Occupational Disease Prevention and Treatment, Guangdong Province Hospital for Occupational Disease Prevention and Treatment, Guangzhou 510-300, PR China
| | - Hanlin Huang
- Guangdong Provincial Key Laboratory of Occupational Disease Prevention and Treatment, Guangdong Province Hospital for Occupational Disease Prevention and Treatment, Guangzhou 510-300, PR China.
| | - Gaku Ichihara
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan; Department of Occupational and Environmental Health, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Noda 278-8510, Japan.
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Saul N, Baberschke N, Chakrabarti S, Stürzenbaum SR, Lieke T, Menzel R, Jonáš A, Steinberg CEW. Two organobromines trigger lifespan, growth, reproductive and transcriptional changes in Caenorhabditis elegans. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2014; 21:10419-10431. [PMID: 24838126 DOI: 10.1007/s11356-014-2932-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 04/15/2014] [Indexed: 06/03/2023]
Abstract
Organobromines of natural and artificial origin are omnipresent in aquatic and terrestrial environments. Although it is well established that exposure to high concentrations of organobromines are harmful to vertebrates, few studies have investigated the effect of environmentally realistic concentrations on invertebrates. Here, the nematode Caenorhabditis elegans was challenged with two organobromines, namely dibromoacetic acid (DBAA) and tetrabromobisphenol-A (TBBP), and monitored for changes in different life trait variables and global gene expression patterns. Fifty micromolar DBAA stimulated the growth and lifespan of the nematodes; however, the onset of reproduction was delayed. In contrast, TBBP changed the lifespan in a hormetic fashion, namely it was stimulated at 0.1 μM but impaired at 50 μM. The reproductive performance was even impaired at 2 μM TBBP. Moreover, DBAA could not reduce the toxic effect of TBBP when applied as a mixture. A whole-genome DNA microarray revealed that both organobromines curtailed signalling and neurological processes. Furthermore on the transcription level, 50 μM TBBP induced proteolysis and DBAA up-regulated biosynthesis and metabolism. To conclude, even naturally occurring concentrations of organobromines can influence the biomolecular responses and life cycle traits in C. elegans. The life extension is accompanied by negative changes in the reproductive behaviour, which is crucial for the stability of populations. Thus, this paper highlights that the effects of exposure to moderate, environmentally realistic concentrations of organobromines should not be ignored.
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Affiliation(s)
- Nadine Saul
- Department of Biology, Freshwater and Stress Ecology, Humboldt-Universität zu Berlin, Späthstr. 80/81, 12437, Berlin, Germany,
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Zhong Z, Zeng T, Xie K, Zhang C, Chen J, Bi Y, Zhao X. Elevation of 4-hydroxynonenal and malondialdehyde modified protein levels in cerebral cortex with cognitive dysfunction in rats exposed to 1-bromopropane. Toxicology 2013; 306:16-23. [PMID: 23395825 DOI: 10.1016/j.tox.2013.01.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2012] [Revised: 01/26/2013] [Accepted: 01/29/2013] [Indexed: 11/16/2022]
Abstract
1-Bromopropane (1-BP), an alternative to ozone-depleting solvents (ODS), exhibits central nervous system (CNS) toxicity in animals and humans. This study was designed to relate CNS damage by Morris water maze (MWM) test and oxidative stress to 1-BP exposure in the rat. Male Wistar rats were randomly divided into 4 groups (n=10), and treated with 0, 200, 400 and 800 mg/kgbw 1-BP for consecutive 12 days, respectively. From day 8 to day 12 of the experiment, MWM test was employed to assess the cognitive function of rats. The cerebral cortex of rats was obtained immediately following the 24h after MWM test conclusion. Glutathione (GSH), oxidized glutathione (GSSG) and total thiol (total-SH) content, GSH reductase (GR) and GSH peroxidase (GSH-Px) activities, malondialdehyde (MDA) level, as well as 4-hydroxynonenal (4-HNE) and MDA modified proteins in homogenates of cerebral cortex were measured. The obtained results showed that 1-BP led to cognitive dysfunction of rats, which was evidenced by delayed escape latency time and swimming distances in MWM performance. GSH and total-SH content, GSH/GSSG ratio, GR activity significantly decreased in cerebral cortex of rats, coupling with the increase of MDA level. 4-HNE and MDA modified protein levels obviously elevated after 1-BP exposure. GSH-Px activities in cerebral cortex of rats also increased. These data suggested that 1-BP resulted in enhanced lipid peroxidation of brain, which might play an important role in CNS damage induced by 1-BP.
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Affiliation(s)
- Zhixia Zhong
- Institute of Toxicology, School of Public Health, Shandong University, Jinan, Shandong Province 250012, China
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Mohideen SS, Ichihara S, Subramanian K, Huang Z, Naito H, Kitoh J, Ichihara G. Effects of exposure to 1-bromopropane on astrocytes and oligodendrocytes in rat brain. J Occup Health 2012. [PMID: 23183024 DOI: 10.1539/joh.12-0118-oa] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVES Human cases of 1-bromopropane (1-BP) toxicity showed ataxic gait and cognitive dysfunction, whereas rat studies showed pyknotic shrinkage in cerebellar Purkinje cells and electrophysiological changes in the hippocampus. The present study investigated the effects of 1-BP on astrocytes and oligodendrocytes in the rat cerebellum and hippocampus to find sensitive markers of central nervous system toxicity. METHODS Forty-eight F344 rats were divided into four equal groups and exposed to 1-BP at 0, 400, 800 and 1,000 ppm for 8 h/day; 7 days/week, for 4 weeks. Nine and three rats per group were used for biochemical and histopathological studies, respectively. RESULTS Kluver-Barrera staining showed pyknotic shrinkage in the cytoplasm of Purkinje cells and nuclei of granular cells in the cerebellum at 1,000 ppm. Immunohistochemical analysis showed increased length of glial fibrillary acidic protein (GFAP)-positive processes of astrocytes in the cerebellum, hippocampus and dentate gyrus at 800 and 1,000 ppm. The myelin basic protein (MBP) level was lower at 1,000 ppm. The numbers of astrocytes and granular cells per tissue volume increased at 400 ppm or higher. CONCLUSION The present study showed that elongation of processes of astrocytes accompanies degeneration of granular cells and Purkinje cells in the cerebellum of the rats exposed to 1-BP. The decrease in MBP and number of oligodendrocytes suggest adverse effects on myelination. The increase in astrocyte population per tissue volume in the cerebellum might be a sensitive marker of 1-BP neurotoxicity, but the underlying mechanism for this change remains elusive.
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Affiliation(s)
- Sahabudeen Sheik Mohideen
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya University, Japan
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Huang Z, Ichihara S, Oikawa S, Chang J, Zhang L, Subramanian K, Mohideen SS, Ichihara G. Proteomic identification of carbonylated proteins in F344 rat hippocampus after 1-bromopropane exposure. Toxicol Appl Pharmacol 2012; 263:44-52. [DOI: 10.1016/j.taap.2012.05.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2012] [Revised: 04/18/2012] [Accepted: 05/26/2012] [Indexed: 01/05/2023]
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10
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Ichihara G, Kitoh J, Li W, Ding X, Ichihara S, Takeuchi Y. Neurotoxicity of 1-bromopropane: Evidence from animal experiments and human studies. J Adv Res 2012. [DOI: 10.1016/j.jare.2011.04.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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11
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Huang Z, Ichihara S, Oikawa S, Chang J, Zhang L, Takahashi M, Subramanian K, Mohideen SS, Wang Y, Ichihara G. Proteomic analysis of hippocampal proteins of F344 rats exposed to 1-bromopropane. Toxicol Appl Pharmacol 2011; 257:93-101. [PMID: 21925529 DOI: 10.1016/j.taap.2011.08.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 08/23/2011] [Accepted: 08/26/2011] [Indexed: 12/28/2022]
Abstract
1-Bromopropane (1-BP) is a compound used as an alternative to ozone-depleting solvents and is neurotoxic both in experimental animals and human. However, the molecular mechanisms of the neurotoxic effects of 1-BP are not well known. To identify the molecular mechanisms of 1-BP-induced neurotoxicity, we analyzed quantitatively changes in protein expression in the hippocampus of rats exposed to 1-BP. Male F344 rats were exposed to 1-BP at 0, 400, or 1000 ppm for 8h/day for 1 or 4 weeks by inhalation. Two-dimensional difference in gel electrophoresis (2D-DIGE) combined with matrix-assisted laser-desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) were conducted to detect and identify protein modification. Changes in selected proteins were further confirmed by western blot. 2D-DIGE identified 26 proteins with consistently altered model (increase or decrease after both 1- and 4-week 1-BP exposures) and significant changes in their levels (p<0.05; fold change ≥ ± 1.2) at least at one exposure level or more compared with the corresponding controls. Of these proteins, 19 were identified by MALDI-TOF-TOF/MS. Linear regression analysis of 1-BP exposure level identified 8 differentially expressed proteins altered in a dose-dependent manner both in 1- and 4-week exposure experiments. The identified proteins could be categorized into diverse functional classes such as nucleocytoplasmic transport, immunity and defense, energy metabolism, ubiquitination-proteasome pathway, neurotransmitter and purine metabolism. Overall, the results suggest that 1-BP-induced hippocampal damage involves oxidative stress, loss of ATP production, neurotransmitter dysfunction and inhibition of ubiquitination-proteasome system.
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Affiliation(s)
- Zhenlie Huang
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
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Mohideen SS, Ichihara G, Ichihara S, Nakamura S. Exposure to 1-bromopropane causes degeneration of noradrenergic axons in the rat brain. Toxicology 2011; 285:67-71. [PMID: 21527306 DOI: 10.1016/j.tox.2011.04.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2011] [Revised: 04/07/2011] [Accepted: 04/08/2011] [Indexed: 11/18/2022]
Abstract
1-Bromopropane (1-BP) has been used as an alternative to ozone-depleting solvents. Previous studies showed that 1-BP is neurotoxic in animals and humans. In humans, exposure to 1-BP caused various neurological and neurobehavioral symptoms or signs including depressive or irritated mood. However, the neurobiological changes underlying the depressive symptoms induced by 1-BP remain to be determined. The depressive symptoms are thought to be associated with degeneration of axons containing noradrenaline and serotonin. Based on this hypothesis, the present study examined the effects of repeated exposure to 1-BP on serotonergic and noradrenergic axons. Exposure to 1-BP induced dose-dependent decreases in the density of noradrenergic axons in the rat prefrontal cortex, but no apparent change in the density of serotonergic axons. The results suggest that depressive symptoms in workers exposed to 1-BP are due, at least in part, to the degeneration of noradrenergic axons in the brain.
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Affiliation(s)
- Sahabudeen Sheik Mohideen
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
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Liu F, Ichihara S, Valentine WM, Itoh K, Yamamoto M, Sheik Mohideen S, Kitoh J, Ichihara G. Increased susceptibility of Nrf2-null mice to 1-bromopropane-induced hepatotoxicity. Toxicol Sci 2010; 115:596-606. [PMID: 20211940 DOI: 10.1093/toxsci/kfq075] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
1-Bromopropane (1-BP) was introduced as an alternative to ozone-depleting solvents. However, it was found to exhibit neurotoxicity, reproductive toxicity, and hepatotoxicity in rodents and neurotoxicity in human. However, the mechanisms underlying the toxicities of 1-BP remain elusive. The present study investigated the role of oxidative stress in 1-BP-induced hepatotoxicity using nuclear factor erythroid 2-related factor 2 (Nrf2)-null mice. Groups of 24 male Nrf2-null mice and 24 male wild-type (WT) C57BL/6J mice were each divided into three groups of eight and exposed to 1-BP at 0, 100, or 300 ppm for 8 h/day for 28 days by inhalation. Liver histopathology showed significantly larger area of necrosis in Nrf2-null mice relative to WT mice at the same exposure level. Nrf2-null mice also had greater malondialdehyde (MDA) levels, higher ratio of oxidized glutathione/reduced form of glutathione, and lower total glutathione content. The constitutive level and the increase in ratio per exposure level of glutathione S-transferase (GST) activity were lower in the liver of Nrf2-null mice than WT mice. Exposure to 1-BP at 300 ppm increased the messenger RNA levels of heme oxygenase-1 (HO-1), glutamate-cysteine ligase modifier subunit (GcLm), glutamate-cysteine synthetase (GcLc), glutathione reductase, and NAD(P)H: quinone oxidoreductase 1 (NQO1) in WT mice but not in Nrf2-null mice except for GST Yc2. Nrf2-null mice were more susceptible to 1-BP-induced hepatotoxicity. That oxidative stress plays a role in 1-BP hepatotoxicity is deduced from the low expression levels and activities of antioxidant enzymes and high MDA levels in Nrf2-null mice.
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Affiliation(s)
- Fang Liu
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
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