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Fueta Y, Ueno S, Ishidao T, Yoshida Y, Kanda Y, Hori H. Exposure to 1-bromopropane vapors during pregnancy enhances the development of hippocampal neuronal excitability in rat pups during lactation. J Occup Health 2020; 62:e12135. [PMID: 32715571 PMCID: PMC7383040 DOI: 10.1002/1348-9585.12135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 04/18/2020] [Accepted: 05/19/2020] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES Although 1-Bromopropane (1-BP) exposure has been reported to cause neurotoxicity in adult humans and animals, its effects on the development of the central nervous system remain unclear. Recently, we reported delayed developmental neurotoxicity (DNT) upon 1-BP exposure in rats. Here we aimed to study the effect of prenatal 1-BP exposure on the hippocampal excitability in the juvenile offspring. METHODS Pregnant Wistar rats were exposed to vaporized 1-BP for 20 days (6 h/d) with concentrations of 0 (control), 400, or 700 ppm. Hippocampal slices were prepared from male offspring during postnatal days (PNDs) 13, 14, and 15. Field excitatory postsynaptic potential (fEPSP) and population spike (PS) were recorded simultaneously from the CA1 region. RESULTS In the exposed groups, the stimulation/response relationships of fEPSP slope and PS amplitude were enhanced more than in the control group at PND 14. Analysis of fEPSP-spike coupling demonstrated increased values of Top and Eslope50 in the exposed groups. Real-time PCR analysis showed a significant increase in the mRNA levels of the adult type Nav 1.1 Na+ channel subunit and the GluR1 glutamate receptor subunit in the hippocampus of the 700 ppm group at PND 14. CONCLUSIONS Our results provide evidence that prenatal exposure to 1-BP accelerates developmental enhancement of hippocampal excitability in the pups before eye-opening. The current study suggests that our evaluation method of DNT is applicable to the industrial chemical 1-BP.
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Affiliation(s)
- Yukiko Fueta
- Department of Environmental Management and ControlSchool of Health SciencesUniversity of Occupational and Environmental HealthKitakyushuJapan
| | - Susumu Ueno
- Department of PharmacologySchool of MedicineUniversity of Occupational and Environmental HealthKitakyushuJapan
| | - Toru Ishidao
- Department of Environmental Management and ControlSchool of Health SciencesUniversity of Occupational and Environmental HealthKitakyushuJapan
| | - Yasuhiro Yoshida
- Department of Immunology and ParasitologySchool of MedicineUniversity of Occupational and Environmental HealthKitakyushuJapan
| | - Yasunari Kanda
- Division of PharmacologyNational Institute of Health SciencesKawasakiJapan
| | - Hajime Hori
- Department of Environmental Management and ControlSchool of Health SciencesUniversity of Occupational and Environmental HealthKitakyushuJapan
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Fueta Y, Ishidao T, Ueno S, Yoshida Y, Kanda Y, Hori H. Prenatal exposure to 1-bromopropane causes delayed adverse effects on hippocampal neuronal excitability in the CA1 subfield of rat offspring. J Occup Health 2017; 60:74-79. [PMID: 29093363 PMCID: PMC5799103 DOI: 10.1539/joh.17-0009-br] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVES Neurotoxicity of 1-bromopropane (1-BP) has been reported in occupational exposure, but whether the chemical exerts developmental neurotoxicity is unknown. We studied the effects of prenatal 1-BP exposure on neuronal excitability in rat offspring. METHODS We exposed dams to 1-BP (700 ppm, 6 h a day for 20 days) and examined hippocampal slices obtained from the male offspring at 2, 5, 8, and 13 weeks of age. We measured the stimulation/response (S/R) relationship and paired-pulse ratios (PPRs) of the population spike (PS) at the interpulse intervals (IPIs) of 5 and 10 ms in the CA1 subfield. RESULTS Prenatal 1-BP exposure enhanced S/R relationships of PS at 2 weeks of age; however, the enhancement diminished at 5 weeks of age until it reached control levels. Prenatal 1-BP exposure decreased PPRs of PS at 2 weeks of age. After sexual maturation, however, the PPRs of PS increased at 5-ms IPI in rats aged 8 and 13 weeks. CONCLUSIONS Our findings indicate that prenatal 1-BP exposure in dams can cause delayed adverse effects on excitability of pyramidal cells in the hippocampal CA1 subfield of offspring.
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Affiliation(s)
- Yukiko Fueta
- Department of Environmental Management and Control, School of Health Sciences, University of Occupational and Environmental Health
| | - Toru Ishidao
- Department of Environmental Management and Control, School of Health Sciences, University of Occupational and Environmental Health
| | - Susumu Ueno
- Department of Occupational Toxicology, University of Occupational and Environmental Health
| | - Yasuhiro Yoshida
- Department of Immunology and Parasitology, School of Medicine, University of Occupational and Environmental Health
| | - Yasunari Kanda
- Division of Pharmacology, National Institute of Health Sciences
| | - Hajime Hori
- Department of Environmental Management and Control, School of Health Sciences, University of Occupational and Environmental Health
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Miao R, Ding B, Zhang Y, Zhao R, Li Y, Zhu B. Large-scale label-free proteomics analysis of occupational poisoned patients of 1-bromopropane, workers exposed to 1-bromopropane and healthy individuals. Hum Exp Toxicol 2017; 37:3-12. [PMID: 28120620 DOI: 10.1177/0960327117689911] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- R Miao
- The 8th People’s Hospital of Wuxi, Wuxi, China
| | - B Ding
- Jiangsu Provincial Center for Disease Prevention and Control, Nanjing, China
| | - Y Zhang
- The 8th People’s Hospital of Wuxi, Wuxi, China
| | - R Zhao
- The 8th People’s Hospital of Wuxi, Wuxi, China
| | - Y Li
- The 8th People’s Hospital of Wuxi, Wuxi, China
| | - B Zhu
- Jiangsu Provincial Center for Disease Prevention and Control, Nanjing, China
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Ishidao T, Fueta Y, Ueno S, Yoshida Y, Hori H. A cross-fostering analysis of bromine ion concentration in rats that inhaled 1-bromopropane vapor. J Occup Health 2016; 58:241-6. [PMID: 27108641 PMCID: PMC5356948 DOI: 10.1539/joh.15-0284-oa] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Objective: Inhaled 1-bromopropane decomposes easily and releases bromine ion. However, the kinetics and transfer of bromine ion into the next generation have not been clarified. In this work, the kinetics of bromine ion transfer to the next generation was investigated by using cross-fostering analysis and a one-compartment model. Methods: Pregnant Wistar rats were exposed to 700 ppm of 1-bromopropane vapor for 6 h per day during gestation days (GDs) 1-20. After birth, cross-fostering was performed between mother exposure groups and mother control groups, and the pups were subdivided into the following four groups: exposure group, postnatal exposure group, gestation exposure group, and control group. Bromine ion concentrations in the brain were measured temporally. Results: Bromine ion concentrations in mother rats were lower than those in virgin rats, and the concentrations in fetuses were higher than those in mothers on GD20. In the postnatal period, the concentrations in the gestation exposure group decreased with time, and the biological half-life was 3.1 days. Conversely, bromine ion concentration in the postnatal exposure group increased until postnatal day 4 and then decreased. This tendency was also observed in the exposure group. A one-compartment model was applied to analyze the behavior of bromine ion concentration in the brain. By taking into account the increase of body weight and change in the bromine ion uptake rate in pups, the bromine ion concentrations in the brains of the rats could be estimated with acceptable precision.
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Affiliation(s)
- Toru Ishidao
- Department of Environmental Management, School of Health Sciences, University of Occupational and Environmental Health
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Prenatal Exposure to 1-Bromopropane Suppresses Kainate-Induced Wet Dog Shakes in Immature Rats. J UOEH 2016; 37:255-61. [PMID: 26667193 DOI: 10.7888/juoeh.37.255] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
1-Bromopropane (1-BP) is used in degreasing solvents and spray adhesives. The adverse effects of 1-BP have been reported in human cases and adult animal models, and its developmental toxicity has also been reported, but its effects on developmental neurotoxicity have not been investigated in detail. We evaluated the effects in rat pups of prenatal exposure to 1-BP on behaviors such as scratching and wet dog shakes (WDS), which were induced by injection of kainate (KA). Pregnant Wistar rats were exposed to vaporized 1-BP with 700 ppm from gestation day 1 to day 20 (6 h/day). KA at doses of 0.1, 0.5, and 2.0 mg/kg were intraperitoneally injected into a control group and a 1-BP-exposed group of pups on postnatal day 14. There was no significant difference in scratching between the control and the prenatally 1-BP-exposed groups, while suppression of the occurrence ratio of WDS was observed at the low dose of 0.1 mg/kg of KA in the prenatally 1-BP-exposed pups. Our results suggest that prenatal exposure to 1-BP affects neurobehavioral responses in the juvenile period.
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KANEMITSU M, FUETA Y, ISHIDAO T, AOU S, HORI H. Development of a direct exposure system for studying the mechanisms of central neurotoxicity caused by volatile organic compounds. INDUSTRIAL HEALTH 2015; 54:42-49. [PMID: 26320726 PMCID: PMC4791292 DOI: 10.2486/indhealth.2015-0076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 08/17/2015] [Indexed: 06/04/2023]
Abstract
Many volatile organic compounds (VOCs) used in work places are neurotoxic. However, it has been difficult to study the cellular mechanisms induced by a direct exposure to neurons because of their high volatility. The objective of this study was to establish a stable system for exposing brain slices to VOCs. With a conventional recording system for brain slices, it is not possible to keep a constant bath concentration of relatively highly volatile solvents, e.g. 1-bromopropane (1-BP). Here we report a new exposure system for VOCs that we developed in which a high concentration of oxygen is dissolved to a perfused medium applying a gas-liquid equilibrium, and in which the tubing is made of Teflon, non adsorptive material. Using our system, the bath concentration of the perfused 1-BP remained stable for at least 2 h in the slice chamber. Both 6.4 and 2.2 mM of 1-BP did not change the paired-pulse response, but fully suppressed long-term potentiation in the dentate gyrus (DG) of hippocampal slices obtained from rats, suggesting that 1-BP decreases synaptic plasticity in the DG at the concentrations tested. Our new system can be applicable for investigating the underlying mechanisms of the neurotoxicity of VOCs at the cellular level.
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Affiliation(s)
- Masanari KANEMITSU
- Department of Environmental Management and Control, School of
Health Sciences, University of Occupational and Environmental Health, Japan
- Department of Brain Science and Engineering, Graduate School
of Life Science and Systems Engineering, Kyushu Institute of Technology, Japan
| | - Yukiko FUETA
- Department of Environmental Management and Control, School of
Health Sciences, University of Occupational and Environmental Health, Japan
| | - Toru ISHIDAO
- Department of Environmental Management and Control, School of
Health Sciences, University of Occupational and Environmental Health, Japan
| | - Shuji AOU
- Department of Brain Science and Engineering, Graduate School
of Life Science and Systems Engineering, Kyushu Institute of Technology, Japan
| | - Hajime HORI
- Department of Environmental Management and Control, School of
Health Sciences, University of Occupational and Environmental Health, Japan
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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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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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Hanley KW, Petersen MR, Cheever KL, Luo L. N-acetyl-S-(n-propyl)-l-cysteine in urine from workers exposed to 1-bromopropane in foam cushion spray adhesives. ANNALS OF OCCUPATIONAL HYGIENE 2009; 53:759-69. [PMID: 19706636 DOI: 10.1093/annhyg/mep051] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
1-Bromopropane (1-BP) has been marketed as an alternative for ozone depleting and other solvents; it is used in aerosol products, adhesives, metal, precision, and electronics cleaning solvents. Mechanisms of toxicity of 1-BP are not fully understood, but it may be a neurological and reproductive toxicant. Sparse exposure information prompted this study using 1-BP air sampling and urinary metabolites. Mercapturic acid conjugates are excreted in urine from 1-BP metabolism involving debromination. Research objectives were to evaluate the utility of urinary N-acetyl-S-(n-propyl)-L-cysteine (AcPrCys) for assessing exposure to 1-BP and compare it to urinary bromide [Br((-))] previously reported for these workers. Forty-eight-hour urine specimens were obtained from 30 workers at two factories where 1-BP spray adhesives were used to construct polyurethane foam seat cushions. Urine specimens were also obtained from 21 unexposed control subjects. All the workers' urine was collected into composite samples representing three time intervals: at work, after work but before bedtime, and upon awakening. Time-weighted average (TWA) geometric mean breathing zone concentrations were 92.4 and 10.5 p.p.m. for spraying and non-spraying jobs, respectively. Urinary AcPrCys showed the same trend as TWA exposures to 1-BP: higher levels were observed for sprayers. Associations of AcPrCys concentrations, adjusted for creatinine, with 1-BP TWA exposure were statistically significant for both sprayers (P < 0.05) and non-sprayers (P < 0.01). Spearman correlation coefficients for AcPrCys and Br((-)) analyses determined from the same urine specimens were highly correlated (P < 0.0001). This study confirms that urinary AcPrCys is an important 1-BP metabolite and an effective biomarker for highly exposed foam cushion workers.
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Affiliation(s)
- Kevin W Hanley
- Division of Surveillance, Hazard Evaluations and Field Studies, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, Ohio, USA.
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Suda M, Honma T, Miyagawa M, Wang RS. Alteration of brain levels of neurotransmitters and amino acids in male F344 rats induced by three-week repeated inhalation exposure to 1-bromopropane. INDUSTRIAL HEALTH 2008; 46:348-359. [PMID: 18716383 DOI: 10.2486/indhealth.46.348] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The present study investigated the effects of 1-bromopropane (1BP) on brain neuroactive substances of rats to determine the extent of its toxicity to the central nervous system (CNS). We measured the changes in neurotransmitters (acetylcholine, catecholamine, serotonin and amino acids) and their metabolites or precursors in eight brain regions after inhalation exposure to 1BP at 50 to 1,000 ppm for 8 h per day for 7 d per week for 3 wk. Rats were sacrificed at 2 h (Case 1), or at 19 h (Case 2) after the end of exposure. In Case 1, the level of 5-hydroxyindoleacetic acid (5HIAA) was lowered in some brain regions by 1BP exposure. The decrease of 5HIAA in the frontal cortex was statistically significant at 50 ppm 1BP exposure. In Case 2, gamma-amino butyric acid (GABA) and taurine were decreased in many brain regions of exposed rats, and a significant decrease of taurine in the midbrain occurred at 50 ppm 1BP exposure. In both cases of 2-h and 19-h intervals from the end of exposure to sacrifice, aspartate and glutamine levels were elevated in many brain regions, but the acetylcholine level did not change in any brain region. Three-week repeated exposure to 1BP produced significantly changes in amino acid contents of rat brains, particularly at 1,000 ppm.
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Affiliation(s)
- Megumi Suda
- National Institute of Occupational Safety and Health (JNIOSH),Kawasaki, Japan
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