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Ferraz da Silva I, Merlo E, Costa CS, Graceli JB, Rodrigues LCM. Tributyltin Exposure Is Associated With Recognition Memory Impairments, Alterations in Estrogen Receptor α Protein Levels, and Oxidative Stress in the Brain of Female Mice. FRONTIERS IN TOXICOLOGY 2022; 3:654077. [PMID: 35295135 PMCID: PMC8915859 DOI: 10.3389/ftox.2021.654077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 03/05/2021] [Indexed: 01/18/2023] Open
Abstract
Tributyltin (TBT) is a persistent organometallic pollutant widely used in several agricultural and industrial processes. TBT exposure is associated with various metabolic, reproductive, immune, and cardiovascular abnormalities. However, few studies have evaluated the effects of TBT on behavior. In the present study, we aimed to investigate whether TBT exposure results in oxidative, neuroendocrine, and behavioral alterations. TBT was administered to adult female mice (250, 500, or 750 ng/kg/day or veh for 14 days), and their recognition memory was assessed. We have also evaluated estrogen receptor (ER)α protein expression and oxidative stress (OS) in brain areas related to memory, as well as the correlation between them. A reduction in short- and long-term recognition memory (STM and LTM) performance, as well as in total exploration time was observed in TBT mice. Reduced ERα protein expression was observed in the prefrontal cortex (PFC) and hippocampus of TBT mice, while an increase in TBARS concentration was observed in the PFC of treated animals. Collectively, these data suggest that TBT exposure impairs recognition memory in female mice as a result of, at least in part, its toxicological effects on ERα expression and OS in specific brain areas related to memory.
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Affiliation(s)
- Igor Ferraz da Silva
- Laboratory of Neurotoxicology and Psychopharmacology, Department of Physiological Sciences, Federal University of Espírito Santo, Vitoria, Brazil
| | - Eduardo Merlo
- Laboratory of Endocrinology and Cellular Toxicology, Department of Morphology, Federal University of Espírito Santo, Vitoria, Brazil
| | - Charles S Costa
- Laboratory of Endocrinology and Cellular Toxicology, Department of Morphology, Federal University of Espírito Santo, Vitoria, Brazil
| | - Jones B Graceli
- Laboratory of Endocrinology and Cellular Toxicology, Department of Morphology, Federal University of Espírito Santo, Vitoria, Brazil
| | - Lívia C M Rodrigues
- Laboratory of Neurotoxicology and Psychopharmacology, Department of Physiological Sciences, Federal University of Espírito Santo, Vitoria, Brazil
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Hoshi T, Toyama T, Shinozaki Y, Koizumi S, Lee JY, Naganuma A, Hwang GW. Evaluation of M1-microglial activation by neurotoxic metals using optimized organotypic cerebral slice cultures. J Toxicol Sci 2019; 44:471-479. [PMID: 31270303 DOI: 10.2131/jts.44.471] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
M1-microglia (neurotoxic microglia) regulate neuronal development and cell death and are involved in many pathologies in the brain. Although organotypic brain slice cultures are widely used to study the crosstalk between neurons and microglia, little is known about the properties of microglia in the mouse cerebral cortex slices. Here, we aimed to optimize the mouse cerebral slice cultures that reflect microglial functions and evaluate the effects of neurotoxic metals on M1-microglial activation. Most microglia in the cerebral slices prepared from postnatal day (P) 7 mice were similar to mature microglia in adult mice brains, but those in the slices prepared from P2 mice were immature, which is a conventional preparation condition. The degree of expression of M1-microglial markers (CD16 and CD32) and inflammatory cytokines (tumor necrosis factor-α and interleukin-1β) by lipopolysaccharide, a representative microglia activator, in the cerebral slices of P7 mice were higher than that in the slices of P2 mice. These results indicate that M1-microglial activation can be evaluated more accurately in the cerebral slices of P7 mice than in those of P2 mice. Therefore, we next examined the effects of various neurotoxic metals on M1-microglial activation using the cerebral slices of P7 mice and found that methylmercury stimulated the activation to M1-microglia, but arsenite, lead, and tributyltin did not induce such activation. Altogether, the optimized mouse cerebral slice cultures used in this study can be a helpful tool to study the influence of various chemicals on the central nervous system in the presence of functionally mature microglia.
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Affiliation(s)
- Takayuki Hoshi
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University
| | - Takashi Toyama
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University
| | - Youichi Shinozaki
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi
| | - Schuichi Koizumi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi
| | - Jin-Yong Lee
- Laboratory of Pharmaceutical Health Sciences, School of Pharmacy, Aichi Gakuin University
| | - Akira Naganuma
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University
| | - Gi-Wook Hwang
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University
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Ofoegbu PU, Simão FCP, Cruz A, Mendo S, Soares AMVM, Pestana JLT. Toxicity of tributyltin (TBT) to the freshwater planarian Schmidtea mediterranea. CHEMOSPHERE 2016; 148:61-67. [PMID: 26802264 DOI: 10.1016/j.chemosphere.2015.12.131] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 12/23/2015] [Accepted: 12/29/2015] [Indexed: 06/05/2023]
Abstract
The freshwater planarian Schmidtea mediterranea, one of the best characterized animal models for regeneration research and developmental biology, is being recognised as a useful species for ecotoxicological studies. Sensitive endpoints related to planarians' behaviour and regeneration can be easily evaluated after exposure to environmental stressors. In this work the sensitivity of S. mediterranea to a gradient of environmentally relevant concentrations of TBT was studied using multiple endpoints like survival, locomotion, head regeneration and DNA damage. In addition, a feeding assay based on planarian's predatory behaviour was performed. Results indicated that TBT is toxic to planarians with LC50's of 1.87 μg L(-1) Sn and 1.31 μg L(-1) Sn at 48 h and 96 h of exposure respectively. Sub-lethal exposures to TBT significantly reduced locomotion and feeding, delayed head regeneration and caused DNA damage in planarians. The behavioural endpoints (feeding and locomotion) and head regeneration were the most sensitive parameters followed by DNA damage. Similar to other aquatic model organisms, S. mediterranea showed high sensitivity towards TBT exposure. Based on our results, and though further research is required concerning their sensitivity to other pollutants, the use of freshwater planarians as a model species in ecotoxicology is discussed.
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Affiliation(s)
- Pearl U Ofoegbu
- Department of Biology & CESAM, University of Aveiro, Portugal; Department of Biology, Federal University of Technology Owerri, Nigeria
| | | | - Andreia Cruz
- Department of Biology & CESAM, University of Aveiro, Portugal
| | - Sónia Mendo
- Department of Biology & CESAM, University of Aveiro, Portugal
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Mitra S, Siddiqui WA, Khandelwal S. C-Phycocyanin protects against acute tributyltin chloride neurotoxicity by modulating glial cell activity along with its anti-oxidant and anti-inflammatory property: A comparative efficacy evaluation with N-acetyl cysteine in adult rat brain. Chem Biol Interact 2015; 238:138-50. [DOI: 10.1016/j.cbi.2015.06.016] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Revised: 05/11/2015] [Accepted: 06/08/2015] [Indexed: 12/28/2022]
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Protective actions of 17β-estradiol and progesterone on oxidative neuronal injury induced by organometallic compounds. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2015:343706. [PMID: 25815107 PMCID: PMC4359856 DOI: 10.1155/2015/343706] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2014] [Accepted: 02/06/2015] [Indexed: 01/10/2023]
Abstract
Steroid hormones synthesized in and secreted from peripheral endocrine glands pass through the blood-brain barrier and play a role in the central nervous system. In addition, the brain possesses an inherent endocrine system and synthesizes steroid hormones known as neurosteroids. Increasing evidence shows that neuroactive steroids protect the central nervous system from various harmful stimuli. Reports show that the neuroprotective actions of steroid hormones attenuate oxidative stress. In this review, we summarize the antioxidative effects of neuroactive steroids, especially 17β-estradiol and progesterone, on neuronal injury in the central nervous system under various pathological conditions, and then describe our recent findings concerning the neuroprotective actions of 17β-estradiol and progesterone on oxidative neuronal injury induced by organometallic compounds, tributyltin, and methylmercury.
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Oyanagi K, Tashiro T, Negishi T. Cell-type-specific and differentiation-status-dependent variations in cytotoxicity of tributyltin in cultured rat cerebral neurons and astrocytes. J Toxicol Sci 2015; 40:459-68. [DOI: 10.2131/jts.40.459] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Koshi Oyanagi
- Department of Chemistry and Biological Science, Aoyama Gakuin University
| | - Tomoko Tashiro
- Department of Chemistry and Biological Science, Aoyama Gakuin University
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Hanana H, Simon G, Kervarec N, Cérantola S. Evaluation of toxicological effects induced by tributyltin in clam Ruditapes decussatus using high-resolution magic angle spinning nuclear magnetic resonance spectroscopy: Study of metabolic responses in heart tissue and detection of a novel metabolite. Toxicol Rep 2014; 1:777-786. [PMID: 28962290 PMCID: PMC5598516 DOI: 10.1016/j.toxrep.2014.09.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Revised: 09/18/2014] [Accepted: 09/18/2014] [Indexed: 12/25/2022] Open
Abstract
Tributyltin (TBT) is a highly toxic pollutant present in many aquatic ecosystems. Its toxicity in mollusks strongly affects their performance and survival. The main purpose of this study was to elucidate the mechanisms of TBT toxicity in clam Ruditapes decussatus by evaluating the metabolic responses of heart tissues, using high-resolution magic angle-spinning nuclear magnetic resonance (HRMAS NMR), after exposure to TBT (10-9, 10-6 and 10-4 M) during 24 h and 72 h. Results show that responses of clam heart tissue to TBT exposure are not dose dependent. Metabolic profile analyses indicated that TBT 10-6 M, contrary to the two other doses tested, led to a significant depletion of taurine and betaine. Glycine levels decreased in all clam groups treated with the organotin. It is suggested that TBT abolished the cytoprotective effect of taurine, betaine and glycine thereby inducing cardiomyopathie. Moreover, results also showed that TBT induced increase in the level of alanine and succinate suggesting the occurrence of anaerobiosis particularly in clam group exposed to the highest dose of TBT. Taken together, these results demonstrate that TBT is a potential toxin with a variety of deleterious effects on clam and this organotin may affect different pathways depending to the used dose. The main finding of this study was the appearance of an original metabolite after TBT treatment likely N-glycine-N'-alanine. It is the first time that this molecule has been identified as a natural compound. Its exact role is unknown and remains to be elucidated. We suppose that its formation could play an important role in clam defense response by attenuating Ca2+ dependent cell death induced by TBT. Therefore this compound could be a promising biomarker for TBT exposure.
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Affiliation(s)
- H Hanana
- Laboratoire de RMN, RPE, Université Européenne de Bretagne, Université de Bretagne Occidentale UFR Sciences et Techniques, 6 avenue le gorgeu, 29238 Brest Cédex3, France
| | - G Simon
- Laboratoire de RMN, RPE, Université Européenne de Bretagne, Université de Bretagne Occidentale UFR Sciences et Techniques, 6 avenue le gorgeu, 29238 Brest Cédex3, France
| | - N Kervarec
- Laboratoire de RMN, RPE, Université Européenne de Bretagne, Université de Bretagne Occidentale UFR Sciences et Techniques, 6 avenue le gorgeu, 29238 Brest Cédex3, France
| | - S Cérantola
- Laboratoire de RMN, RPE, Université Européenne de Bretagne, Université de Bretagne Occidentale UFR Sciences et Techniques, 6 avenue le gorgeu, 29238 Brest Cédex3, France
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Mitra S, Siddiqui WA, Khandelwal S. Early cellular responses against tributyltin chloride exposure in primary cultures derived from various brain regions. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2014; 37:1048-1059. [PMID: 24762416 DOI: 10.1016/j.etap.2014.03.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 03/24/2014] [Accepted: 03/30/2014] [Indexed: 06/03/2023]
Abstract
Tributyltin (TBT) is a potent biocide and commonly used in various industrial sectors. Humans are mainly exposed through the food chain. We have previously demonstrated tin accumulation in brain following TBT-chloride (TBTC) exposure. In this study, effect of TBTC on dissociated cells from different brain regions was evaluated. Cytotoxicity assay (MTT), mode of cell death (Annexin V/PI assay), oxidative stress parameters (ROS and lipid peroxidation), reducing power of the cell (GSH), mitochondrial membrane potential (MMP) and intracellular Ca(2+) were evaluated to ascertain the effect of TBTC. Expression of glial fibrillary acidic protein (GFAP) was measured to understand the effect on astroglial cells. TBTC as low as 30 nM was found to reduce GSH levels, whereas higher doses of 300 and 3000 nM induced ROS generation and marked loss in cell viability mainly through apoptosis. Striatum showed higher susceptibility than other regions, which may have further implications on various neurological aspects.
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Affiliation(s)
- Sumonto Mitra
- Immunotoxicology Division, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Lucknow, India; Department of Biochemistry, Faculty of Science, Jamia Hamdard (Hamdard University), New Delhi, India.
| | - Waseem A Siddiqui
- Department of Biochemistry, Faculty of Science, Jamia Hamdard (Hamdard University), New Delhi, India
| | - Shashi Khandelwal
- Immunotoxicology Division, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Lucknow, India.
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Ishihara Y, Fujitani N, Kawami T, Adachi C, Ishida A, Yamazaki T. Suppressive effects of 17β-estradiol on tributyltin-induced neuronal injury via Akt activation and subsequent attenuation of oxidative stress. Life Sci 2014; 99:24-30. [PMID: 24486302 DOI: 10.1016/j.lfs.2014.01.061] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 12/19/2013] [Accepted: 01/13/2014] [Indexed: 11/24/2022]
Abstract
AIMS Neuroactive steroids are reported to protect neurons from various harmful compounds; however, the protective mechanisms remain largely unclear. In this study, we examined the suppressive effects of 17β-estradiol (E2) on tributyltin (TBT)-induced neurotoxicity. MAIN METHODS Organotypic hippocampal slices were prepared from neonatal rats and then cultured. Cell death was assayed by propidium iodide uptake. Levels of reactive oxygen species (ROS) were determined by dihydroethidium staining. Protein phosphorylation was evaluated by immunoblotting. KEY FINDINGS Pretreatment of the slices with E2 dose-dependently attenuated the neuronal injury induced by TBT. An estrogen receptor antagonist, ICI182,780 abrogated these neuroprotective effects. The de novo protein synthesis inhibitors actinomycin D and cycloheximide showed no effects on the neuroprotective mechanism, indicating that a nongenomic pathway acting via the estrogen receptor may be involved in the neuroprotection conferred by E2. E2 suppressed the ROS production and lipid peroxidation induced by TBT, and these effects were almost completely canceled by ICI182,780. TBT decreased Akt phosphorylation, and this reduction was suppressed by E2. An Akt inhibitor, triciribine, attenuated the decreases in both the ROS production and neuronal injury mediated by E2. SIGNIFICANCE E2 enhances the phosphorylation of Akt, thereby attenuating the oxidative stress and subsequent neuronal injury induced by TBT.
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Affiliation(s)
- Yasuhiro Ishihara
- Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima 739-8521, Japan.
| | - Noriko Fujitani
- Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima 739-8521, Japan
| | - Tomohito Kawami
- Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima 739-8521, Japan
| | - Chika Adachi
- Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima 739-8521, Japan
| | - Atsuhiko Ishida
- Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima 739-8521, Japan
| | - Takeshi Yamazaki
- Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima 739-8521, Japan
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Abstract
Hippocampal functions are influenced by steroid hormones, such as testosterone and estradiol. It has been demonstrated that hippocampus-derived steroid hormones play important roles in neuronal protection and synapse formation. Our research groups have demonstrated that estradiol is de novo synthesized in the rat hippocampus. However, the mechanism(s) regulating this synthesis remains unclear. It has been reported that tributyltin, an environmental pollutant, binds to the retinoid X receptor (RXR) and modifies estrogen synthesis in human granulosa-like tumor cells. This compound can penetrate the blood brain barrier, and tends to accumulate in the brain. Based on these facts, we hypothesized that tributyltin could influence the hippocampal estradiol synthesis. A concentration of 0.1 μM tributyltin induced an increase in the mRNA content of P450(17α) and P450arom in hippocampal slices, as determined using real-time PCR. The transcript levels of other steroidogenic enzymes and a steroidogenic acute regulatory protein were not affected. The estradiol level in rat hippocampal slices was subsequently determined using a radioimmunoassay. We found that the estradiol synthesis was stimulated by ∼2-fold following a 48-h treatment with 0.1 μM tributyltin, and this was accompanied by transcriptional activation of P450(17α) and P450arom. Tributyltin stimulated de novo hippocampal estradiol synthesis by modifying the transcription of specific steroidogenic enzymes.
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Affiliation(s)
- Eiji Munetsuna
- Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University , Higashihiroshima , Japan
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Ferreira M, Blanco L, Garrido A, Vieites JM, Cabado AG. In vitro approaches to evaluate toxicity induced by organotin compounds tributyltin (TBT), dibutyltin (DBT), and monobutyltin (MBT) in neuroblastoma cells. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2013; 61:4195-4203. [PMID: 23534342 DOI: 10.1021/jf3050186] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The toxic effects of the organotin compounds (OTCs) monobutyltin (MBT), dibutyltin (DBT), and tributyltin (TBT) were evaluated in vitro in a neuroblastoma human cell line. Mechanisms of cell death, apoptosis versus necrosis, were studied by using several markers: inhibition of cell viability and proliferation, F-actin, and mitochondrial membrane potential changes as well as reactive oxygen species (ROS) production and DNA fragmentation. The most toxic effects were detected with DBT and TBT even at very low concentrations (0.1-1 μM). In contrast, MBT induced lighter cytotoxic changes at the higher doses tested. None of the studied compounds stimulated propidium iodide uptake, although the most toxic chemical, TBT, caused lactate dehydrogenase release at the higher concentrations tested. These findings suggest that in neuroblastoma, OTC-induced cytotoxicity involves different pathways depending on the compound, concentration, and incubation time. A screening method for DBT and TBT quantification based on cell viability loss was developed, allowing a fast detection alternative to complex methodology.
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Affiliation(s)
- Martiña Ferreira
- Food Safety Division, ANFACO-CECOPESCA, Campus Univ. 16, 36310 Vigo PO, Spain
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12
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Pagliarani A, Nesci S, Ventrella V. Toxicity of organotin compounds: Shared and unshared biochemical targets and mechanisms in animal cells. Toxicol In Vitro 2013; 27:978-90. [DOI: 10.1016/j.tiv.2012.12.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Revised: 11/08/2012] [Accepted: 12/03/2012] [Indexed: 01/10/2023]
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Ishihara Y, Kawami T, Ishida A, Yamazaki T. Tributyltin induces oxidative stress and neuronal injury by inhibiting glutathione S-transferase in rat organotypic hippocampal slice cultures. Neurochem Int 2012; 60:782-90. [PMID: 22449404 DOI: 10.1016/j.neuint.2012.03.004] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 03/03/2012] [Accepted: 03/08/2012] [Indexed: 11/19/2022]
Abstract
Tributyltin (TBT) has been used as a heat stabilizer, agricultural pesticide and antifouling agents on ships, boats and fish-farming nets; however, the neurotoxicity of TBT has recently become a concern. TBT is suggested to stimulate the generation of reactive oxygen species (ROS) inside cells. The aim of this study was to determine the mechanism of neuronal oxidative injury induced by TBT using rat organotypic hippocampal slice cultures. The treatment of rat hippocampal slices with TBT induced ROS production, lipid peroxidation and cell death. Pretreatment with antioxidants such as superoxide dismutase, catalase or trolox, suppressed the above phenomena induced by TBT, indicating that TBT elicits oxidative stress in hippocampal slices, which causes neuronal cell death. TBT dose-dependently inhibited glutathione S-transferase (GST), but not glutathione peroxidase or glutathione reductase in the cytosol of rat hippocampus. The treatment of hippocampal slices with TBT decreased the GST activity. Pretreatment with reduced glutathione attenuated the reduction of GST activity and cell death induced by TBT, indicating that the decrease in GST activity by TBT is involved in hippocampal cell death. When hippocampal slices were treated with sulforaphane, the expression and activity of GST were increased. Notably, TBT-induced oxidative stress and cell death were significantly suppressed by pretreatment with sulforaphane. These results indicate that GST inhibition could contribute, at least in part, to the neuronal cell death induced by TBT in hippocampal slices. This study is the first report to show the link between neuronal oxidative injury and the GST inhibition elicited by TBT.
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Affiliation(s)
- Yasuhiro Ishihara
- Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, Japan.
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Sasaya H, Yasuzumi K, Maruoka H, Fujita A, Kato Y, Waki T, Shimoke K, Ikeuchi T. Apoptosis-inducing activity of endocrine-disrupting chemicals in cultured PC12 cells. ACTA ACUST UNITED AC 2012. [DOI: 10.4236/abc.2012.22012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Essawy AE, El-Sherief SS, Sadek IA, Soffar AA. Neuropathological Effect of Tributyltin on the Cerebral Ganglia of the Land Snail, Eobania vermiculata. ACTA ACUST UNITED AC 2011. [DOI: 10.3923/ijzr.2011.252.262] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Neurodegenerative effects of recombinant HIV-1 Tat(1-86) are associated with inhibition of microtubule formation and oxidative stress-related reductions in microtubule-associated protein-2(a,b). Neurochem Res 2011; 36:819-28. [PMID: 21259049 DOI: 10.1007/s11064-011-0409-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/10/2011] [Indexed: 01/09/2023]
Abstract
The human immunodeficiency virus 1 (HIV-1) protein Trans-activator of Transcription (Tat) is a nuclear regulatory protein that may contribute to the development of HIV-1 associated dementia by disrupting the neuronal cytoskeleton. The present studies examined effects of recombinant Tat(1-86; 1-100 nM) on microtubule-associated protein (MAP)-dependent and MAP-independent microtubule formation ex vivo and oxidative neuronal injury in rat organotypic hippocampal explants. Acute exposure to Tat(1-86) (≥1 nM) markedly reduced MAP-dependent and -independent microtubule formation ex vivo, as did vincristine sulfate (0.1-10 μM). Cytotoxicity, as measured by propidium iodide uptake, was observed in granule cells of the DG with exposure to 100 nM Tat(1-86) for 24 or 72 h, while significant reductions in MAP-2 immunoreactivity were observed in granule cells and pyramidal cells of the CA1 and CA3 regions at each timepoint. These effects were prevented by co-exposure to the soluble vitamin E analog Trolox (500 μM). Thus, effects of Tat(1-86) on the neuronal viability may be associated with direct interactions with microtubules and generation of oxidative stress.
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Watanabe KH, Andersen ME, Basu N, Carvan MJ, Crofton KM, King KA, Suñol C, Tiffany-Castiglioni E, Schultz IR. Defining and modeling known adverse outcome pathways: Domoic acid and neuronal signaling as a case study. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2011; 30:9-21. [PMID: 20963854 DOI: 10.1002/etc.373] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
An adverse outcome pathway (AOP) is a sequence of key events from a molecular-level initiating event and an ensuing cascade of steps to an adverse outcome with population-level significance. To implement a predictive strategy for ecotoxicology, the multiscale nature of an AOP requires computational models to link salient processes (e.g., in chemical uptake, toxicokinetics, toxicodynamics, and population dynamics). A case study with domoic acid was used to demonstrate strategies and enable generic recommendations for developing computational models in an effort to move toward a toxicity testing paradigm focused on toxicity pathway perturbations applicable to ecological risk assessment. Domoic acid, an algal toxin with adverse effects on both wildlife and humans, is a potent agonist for kainate receptors (ionotropic glutamate receptors whose activation leads to the influx of Na(+) and Ca²(+)). Increased Ca²(+) concentrations result in neuronal excitotoxicity and cell death, primarily in the hippocampus, which produces seizures, impairs learning and memory, and alters behavior in some species. Altered neuronal Ca²(+) is a key process in domoic acid toxicity, which can be evaluated in vitro. Furthermore, results of these assays would be amenable to mechanistic modeling for identifying domoic acid concentrations and Ca²(+) perturbations that are normal, adaptive, or clearly toxic. In vitro assays with outputs amenable to measurement in exposed populations can link in vitro to in vivo conditions, and toxicokinetic information will aid in linking in vitro results to the individual organism. Development of an AOP required an iterative process with three important outcomes: a critically reviewed, stressor-specific AOP; identification of key processes suitable for evaluation with in vitro assays; and strategies for model development.
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Yamada J, Inoue K, Furukawa T, Fukuda A. Low-concentration tributyltin perturbs inhibitory synaptogenesis and induces neuronal death in immature but not mature neurons. Toxicol Lett 2010; 198:282-8. [PMID: 20659539 DOI: 10.1016/j.toxlet.2010.07.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 07/18/2010] [Accepted: 07/19/2010] [Indexed: 02/01/2023]
Abstract
Tributyltin (TBT) has harmful effects on invertebrates. Reports indicate that intoxication of humans with organotin compounds could be associated with neurological symptoms such as epilepsy and amnesia; however, the toxicity mechanisms in mammals are unknown. TBT acts as a Cl(-)/OH(-) antiporter, and likely affects the GABAergic system by disturbing Cl(-) homeostasis. This study aimed to elucidate neurotoxic actions of TBT on mouse neocortical neurons during development. From 4 days in vitro (4 DIV) or 14 DIV in culture, cortical neurons were exposed to TBT continuously for 3 days. TBT-induced neuronal death at 30nM during DIV 4-6, and at 50nM during DIV 14-16. To further characterize this age-dependent cytotoxicity, miniature postsynaptic currents (mPSCs) were analyzed by whole-cell patch-clamp. The frequency of mPSCs was significantly reduced by treatment with 30nM TBT during DIV 4-6, but not DIV 14-16. After TBT treatment during DIV 4-6, GABA(A) receptor-mediated reversal potentials (E(GABA)) were significantly shifted negatively. The TBT-induced E(GABA) shift and neuronal death were reversed by increment of extracellular Cl(-) concentration, suggesting that disruption of Cl(-) homeostasis underlies the disturbance of neuronal ontogeny induced by TBT. These data indicate that the TBT may affect synaptogenesis and neuronal survival, particularly in early development.
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Affiliation(s)
- Junko Yamada
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan.
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Munetsuna E, Hojo Y, Hattori M, Ishii H, Kawato S, Ishida A, Kominami SAJ, Yamazaki T. Retinoic acid stimulates 17beta-estradiol and testosterone synthesis in rat hippocampal slice cultures. Endocrinology 2009; 150:4260-9. [PMID: 19497980 DOI: 10.1210/en.2008-1644] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The hippocampus is essentially involved in learning and memory processes. Its functions are affected by various neuromodulators, including 17beta-estradiol, testosterone, and retinoid. Brain-synthesized steroid hormones act as autocrine and paracrine modulators. The regulatory mechanism underlying brain steroidogenesis has not been fully elucidated. Synthesis of sex steroids in the gonads is stimulated by retinoic acids. Therefore, we examined the effects of retinoic acids on estradiol and testosterone biosynthesis in the rat hippocampus. We used cultured hippocampal slices from 10- to 12-d-old male rats to investigate de novo steroidogenesis. The infant rat hippocampus possesses mRNAs for steroidogenic enzymes and retinoid receptors. Slices were used after 24 h of preculture to obtain maximal steroidogenic activity because steroidogenesis in cultured slices decreases with time. The mRNA levels for P450(17alpha), P450 aromatase and estrogen receptor-beta in the slices were increased by treatment with 9-cis-retinoic acid but not by all-trans-isomer. The magnitude of stimulation and the shape of the dose-response curve for the mRNA level for P450(17alpha) were similar to those for cellular retinoid binding protein type 2, the transcription of which is activated by retinoid X receptor signaling. 9-cis-Retinoic acid also induced a 1.7-fold increase in the protein content of P450(17alpha) and a 2-fold increase in de novo synthesis of 17beta-estradiol and testosterone. These steroids may be synthesized from a steroid precursor(s), such as pregnenolone or other steroids, or from cholesterol, as so-called neurosteroids. The stimulation of estradiol and testosterone synthesis by 9-cis-retinoic acid might be caused by activation of P450(17alpha) transcription via retinoid X receptor signaling.
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Affiliation(s)
- Eiji Munetsuna
- Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima 739-8521, Japan
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Unno T, Iida R, Okawa M, Matsuyama H, Hossain MM, Kobayashi H, Komori S. Tributyltin-induced Ca(2+) mobilization via L-type voltage-dependent Ca(2+) channels in PC12 cells. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2009; 28:70-77. [PMID: 21783984 DOI: 10.1016/j.etap.2009.02.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Revised: 02/12/2009] [Accepted: 02/13/2009] [Indexed: 05/31/2023]
Abstract
The effects of tributyltin (TBT) on cytosolic Ca(2+) concentration ([Ca(2+)](c)) and cell viability were investigated in nerve growth factor-differentiated PC12 cells. TBT concentration dependently increased [Ca(2+)](c) with an EC(50) value of 0.07μM. This effect was markedly reduced by removal of the extracellular Ca(2+) or membrane depolarization with a high K(+) medium, but unaffected by thapsigargin causing depletion of intracellular Ca(2+) stores. The L-type voltage-dependent Ca(2+) channel (VDCC) blocker nicardipine blocked the effect of TBT, but the N-type VDCC blocker ω-conotoxin did not. TBT decreased the number of viable cells with an EC(50) value of 0.09μM. The TBT-induced cell death was prevented by nicardipine or by chelating the cytosolic Ca(2+) with BAPTA-AM, but not by ω-conotoxin. The results show that TBT causes an increase in [Ca(2+)](c) via activating L-type VDCCs, and support the idea that the organotin-induced cell death arises through Ca(2+) mobilization via L-type VDCCs.
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Affiliation(s)
- Toshihiro Unno
- Laboratory of Veterinary Pharmacology, Department of Veterinary Medicine, Faculty of Applied Biological Science, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan; Department of Pathogenetic Veterinary Science, United Graduate School of Veterinary Science, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
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Zuo Z, Cai J, Wang X, Li B, Wang C, Chen Y. Acute administration of tributyltin and trimethyltin modulate glutamate and N-methyl-D-aspartate receptor signaling pathway in Sebastiscus marmoratus. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2009; 92:44-49. [PMID: 19223082 DOI: 10.1016/j.aquatox.2009.01.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Revised: 01/11/2009] [Accepted: 01/16/2009] [Indexed: 05/27/2023]
Abstract
Tributyltin (TBT), widely used as an antifouling biocide, is the most abundant pesticide in coastal environments. Trimethyltin (TMT) is a potent neurotoxicant of a mechanism of action yet to be uncovered. The neurotoxicity of TBT and TMT on the brain of marine fish Sebastiscus marmoratus was investigated in this study. The results showed that TBT and TMT can modulate amino acid neurotransmitters and N-methyl-D-aspartate receptor (NMDAR) signaling pathway in the brain of marine fish in a different manner. TBT did not increase the content of the amino acid neurotransmitters except gamma-aminobutyricd acid (GABA). TMT increased the content of aspartate (Asp), glutamate (Glu) and GABA in a dose-dependent manner. The expression of NADAR and components on its signaling pathway, such as calmodulin, calmodulin-dependent kinase II (CaMKII) and cAMP-response element-binding (CREB) protein was significantly decreased in a dose-dependent manner after TBT exposure. However, the low dose of TMT exposure up-regulate rather than down-regulate the expression of NMDAR and other genes of its pathway. It is suggested that the Glu-NMDAR pathway plays a role in the mechanism for the brain injury in marine fish after TBT or TMT exposure. The alteration of expression of glutamatergic receptor NMDAR and components on its signaling pathway accompanied with the change of total brain transmitter level indicated the importance of glutamatergic system in organotin toxicity.
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Affiliation(s)
- Zhenghong Zuo
- Key Laboratory of the Ministry of Education for Cell Biology and Tumor Cell Engineering, School of Life Sciences, Xiamen University, Siming South Road, Xiamen City 361005, PR China.
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Zhang H, Zhang J, Chen Y, Zhu Y. Microcystin-RR induces apoptosis in fish lymphocytes by generating reactive oxygen species and causing mitochondrial damage. FISH PHYSIOLOGY AND BIOCHEMISTRY 2008; 34:307-312. [PMID: 18958587 DOI: 10.1007/s10695-007-9189-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2007] [Accepted: 10/19/2007] [Indexed: 05/27/2023]
Abstract
Microcystin-RR (MCRR), a very widespread toxic microcystin in China, has previously been proved to induce sensitive apoptosis in Carassius auratus lymphocytes in vitro. This study focused on the role of intracellular Ca(2+), mitochondrial membrane potential, reactive oxygen species, and intracellular ATP in the mechanism of MCRR-induced apoptotic toxicity to fish lymphocytes. Compared with controls, administration of MCRR (10 nmol L(-1)) caused a massive calcium influx resulting in elevation of reactive oxygen species (ROS), rapid disruption of mitochondrial membrane potential (DeltaPsim), and depletion of ATP. This study provided a possible mechanism for the cytotoxicity of microcystins to fish lymphocytes.
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Affiliation(s)
- H Zhang
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310028, PR China
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Zhang J, Zuo Z, Chen R, Chen Y, Wang C. Tributyltin exposure causes brain damage in Sebastiscus marmoratus. CHEMOSPHERE 2008; 73:337-343. [PMID: 18644613 DOI: 10.1016/j.chemosphere.2008.05.072] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2007] [Revised: 05/03/2008] [Accepted: 05/27/2008] [Indexed: 05/26/2023]
Abstract
Tributyltin (TBT) is a ubiquitous marine environmental contaminant characterized primarily by its reproductive toxicity. However, the neurotoxic effect of TBT has not been extensively described, especially in fishes which have a high number of species in the marine environment. This study was conducted to investigate the neurotoxic effects of TBT at environmental levels (1, 10, and 100ngl(-1)) on female Sebastiscus marmoratus. The results showed that TBT exposure induced apoptosis in brain cells of three regions including the pallial areas of the telencephalon, the granular layer of the optic tectum, and the cerebellum. In addition, the increase of reactive oxygen species and nitric oxide levels, and the decrease of Na+/K+-ATPase activity were found in the brain. The results strongly indicated neurotoxicity of TBT to fishes. According to the regions in which apoptosis was found in the brain, TBT exposure might influence the schooling, sensory and motorial functions of fishes.
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Affiliation(s)
- Jiliang Zhang
- Key Laboratory of the Ministry of Education for Cell Biology and Tumor Cell Engineering, School of Life Sciences, Xiamen University, Xiamen 361005, China
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Tada-Oikawa S, Kato T, Kuribayashi K, Nishino K, Murata M, Kawanishi S. Critical role of hydrogen peroxide in the differential susceptibility of Th1 and Th2 cells to tributyltin-induced apoptosis. Biochem Pharmacol 2008; 75:552-61. [DOI: 10.1016/j.bcp.2007.09.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2007] [Revised: 09/10/2007] [Accepted: 09/11/2007] [Indexed: 10/22/2022]
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Zhang H, Zhang J, Chen Y, Zhu Y. Influence of intracellular Ca(2+), mitochondria membrane potential, reactive oxygen species, and intracellular ATP on the mechanism of microcystin-LR induced apoptosis in Carassius auratus lymphocytes in vitro. ENVIRONMENTAL TOXICOLOGY 2007; 22:559-564. [PMID: 18000843 DOI: 10.1002/tox.20296] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Microcystin-LR (MCLR), the most toxic microcystin up to date, could induce apoptosis in many kinds of fish and mammalian cells. For the fish immunotoxicity, it was found that MCLR could induce apoptosis in Carassius auratus lymphocytes in vitro. So this study focused on the role of intracellular Ca(2+), mitochondrial membrane potential, reactive oxygen species (ROS), and intracellular ATP in response to the mechanisms of MCLR-induced apoptosis in fish lymphocytes. MCLR (10 nM) administration resulted in a massive elevation in ROS, intracellular Ca(2+), decreased ATP, and rapid mitochondrial membrane potential (DeltaPsi(m)) disruption. When compared to controls, both a fourfold significant (P < 0.001) elevation in O(2) (-) in 1.5 h and an approximately twofold increase in Ca(2+) in 0.5 h were observed. After 6 h of treatment, an approximately 30% decrease for DeltaPsi(m) but about 75% decline for ATP were found. Together, the results demonstrated that MCLR-induced apoptosis was associated with a massive calcium influx, resulting in O(2) (-) elevation, DeltaPsi(m) disruption, and ATP depletion. This study provided a possible cytotoxic mechanism of fish lymphocytes caused by MCLR.
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Affiliation(s)
- H Zhang
- Research Center for Eco-Environmental Sciences, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310028, People's Republic of China
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Kim YM, Lee JJ, Park SK, Lim SC, Hwang BY, Lee CK, Lee MK. Effects of tri butyl tin acetate on dopamine biosynthesis and l-dopa-lnduced cytotoxicity in pc12 cells. Arch Pharm Res 2007; 30:858-65. [PMID: 17703738 DOI: 10.1007/bf02978837] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The effects of tributyltin acetate (TBTA) on dopamine biosynthesis and L-3,4-dihydroxyphenylalanine (L-DOPA)-induced cytotoxicity in PC12 cells were examined. TBTA at concentrations of 0.1-0.2 microM inhibited dopamine biosynthesis by reducing tyrosine hydroxylase (TH) activity and TH gene expression in PC12 cells. TBTA at 0.1-0.4 microM also reduced L-DOPA (20-50 microM)-induced increases in dopamine content for 24 h in PC12 cells. TBTA at concentrations up to 0.3 microM did not affect cell viability. However, TBTA at concentrations higher than 0.4 microM caused apoptotic cytotoxicity. Exposure of PC12 cells to non-cytotoxic (0.1 and 0.2 microM) or cytotoxic (0.4 microM) concentrations of TBTA with L-DOPA (20, 50 and 100 microM) significantly increased the cell loss and the percentage of apoptotic cells after 24 or 48 h compared with TBTA or L-DOPA alone. These data suggest that TBTA inhibits dopamine biosynthesis and enhances L-DOPA-induced cytotoxicity in PC12 cells.
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Affiliation(s)
- Yu Mi Kim
- College of Pharmacy and Research Center for Bioresource and Health, Chungbuk National University, 12, Gaeshin-Dong, Heungduk-Gu, Cheongju 361-763, Korea
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Lee JJ, Kim YM, Park SK, Lee MK. Effects of tributyltin chloride on L-DOPA-induced cytotoxicity in PC12 cells. Arch Pharm Res 2006; 29:645-50. [PMID: 16964759 DOI: 10.1007/bf02968248] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Tributyltin chloride (TBTC) at concentrations of 0.5-1.0 microM inhibits dopamine biosynthesis in PC12 cells. In this study, the effects of TBTC on L-3,4-dihydroxyphenylalanine (L-DOPA)-induced cytotoxicity in PC12 cells were investigated. TBTC at concentrations up to 1.0 microM neither affected cell viability, nor induced apoptosis after 24 or 48 h in PC12 cells. However, TBTC at concentrations higher than 2.0 microM caused cytotoxicity through an apoptotic process. In addition, exposure of PC12 cells to non-cytotoxic (0.5 and 1.0 microM) or cytotoxic (2.0 microM) concentrations of TBTC in combination with L-DOPA (20, 50 and 100 microM) resulted in a significant increase in cell loss and the percentage of apoptotic cells after 24 or 48 h compared with TBTC or L-DOPA alone. The enhancing effects of TBTC on L-DOPA-induced cytotoxicity were concentration- and treatment time-dependent. These data demonstrate that TBTC enhances L-DOPA-induced cytotoxicity in PC 12 cells.
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Affiliation(s)
- Jae Joon Lee
- College of Pharmacy, and Research Center for Bioresource and Health, Chungbuk National University, Cheongju 361-763, Korea
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Nakatsu Y, Kotake Y, Ohta S. Tributyltin-induced cell death is mediated by calpain in PC12 cells. Neurotoxicology 2006; 27:587-93. [PMID: 16678266 DOI: 10.1016/j.neuro.2006.03.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2005] [Revised: 03/15/2006] [Accepted: 03/15/2006] [Indexed: 10/24/2022]
Abstract
Tributyltin, an endocrine-disrupting chemical, has been used as a heat stabilizer, agricultural pesticide and component of antifouling paints. In this study, we investigated whether calpain is involved in tributyltin toxicity in undifferentiated PC12 cells. Tributyltin (2 microM) induced an increase of lactate dehydrogenase release, a marker of cytotoxicity, in PC12 cells in a time-dependent manner. It also induced calpain activation in a dose-dependent manner, and a calpain inhibitor, MDL28170 (40 microM), decreased the cellular toxicity, suggesting that calpain is involved in tributyltin toxicity in PC12 cells. Because calpain is a calcium-dependent protease, we examined the effect of EGTA, an extracellular Ca(2+) chelator and BAPTA-AM, an intracellular Ca(2+) chelator. Calpain activation induced by tributyltin was decreased by BAPTA-AM (50 microM), but not by EGTA (1 mM), suggesting that calpain activation is associated with calcium release from intracellular Ca(2+) stores. Further, we investigated the relationship between caspase-3 and calpain. Inhibition of caspase-3 reduced calpain activity induced by tributyltin. In conclusion, we have demonstrated that tributyltin induced cell death through calpain activation, and that intracellular Ca(2+) increase and caspase-3 activation are required for calpain activation by tributyltin.
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Affiliation(s)
- Yusuke Nakatsu
- Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
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Liu XM, Shao JZ, Xiang LX, Chen XY. Cytotoxic effects and apoptosis induction of atrazine in a grass carp (Ctenopharyngodon idellus) cell line. ENVIRONMENTAL TOXICOLOGY 2006; 21:80-9. [PMID: 16463256 DOI: 10.1002/tox.20159] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Atrazine is a widely used herbicide that was considered to be an endocrine disrupter capable of interfering with the synthesis and action of natural hormones. In the present study, we found that atrazine was able to cause apoptosis in grass carp (Ctenopharyngodon idellus) cells from cell line ZC7901. By fluorescent and transmission electron microscopy, the atrazine-incubated cells displayed a series of morphological changes, including condensation of the nucleus, margination of chromatin to form dense granular caps, and formation of apoptotic bodies. Moreover, DNA fragmentation was detected by the TUNEL reaction and agarose gel electrophoresis. These typical characteristics of cells undergoing apoptosis indicated the occurrence of apoptosis in ZC7901. Apoptosis induced by atrazine was dose- and time-dependent and was involved in mitochondrial membrane potential (DeltaPsi(m)) disruption, elevation in intracellular Ca(2+), generation of reactive oxygen species, and intracellular ATP depletion. This study provides the first evidence that atrazine was able to induce apoptosis in fish cells, which indicated the existence of a novel cytotoxic mechanism caused by atrazine and may improve our understanding of the complex relationship between contaminants and aquatic organisms.
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Affiliation(s)
- Xin-Mei Liu
- College of Life Sciences, Zhejiang University, Hangzhou 310012, People's Republic of China
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Yamazaki T, Shimodaira M, Kuwahara H, Wakatsuki H, Horiuchi H, Matsuda H, Kominami S. Tributyltin disturbs bovine adrenal steroidogenesis by two modes of action. Steroids 2005; 70:913-21. [PMID: 16038956 DOI: 10.1016/j.steroids.2005.06.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2004] [Revised: 05/10/2005] [Accepted: 06/10/2005] [Indexed: 11/28/2022]
Abstract
Tributyltin, an environmental pollutant, affected adrenal steroid hormone biosynthesis by two modes of action. Treatment of bovine adrenal cultured cells with 10-100 nM tributyltin for 48 h suppressed cortisol and androstenedione secretion, but induced the accumulation of 17alpha-hydroxyprogesterone and deoxycortisol, indicating that the P450(C21) and P450(11beta) activities were specifically suppressed. Direct inhibition of the enzymatic activities due to tributyltin was not observed in isolated organelles of untreated cells at concentrations less than 10 microM. Western blotting experiments using specific antibodies against steroidogenic enzymes showed that treatment with 1-100 nM tributyltin caused a decrease in cellular P450(C21) and P450(11beta) protein levels, and real-time PCR experiments showed that the decrease in protein content was attributable to decreases in mRNA of the enzymes. Tributyltin at concentrations higher than 100 nM suppressed all steroid biosynthesis in the adrenal cells. This suppression was closely correlated to the decrease in steroidogenic acute regulatory protein. Since nanomolar concentrations of tributyltin disturbed steroidogenesis in mammalian cells, there is the possibility that steroid hormone synthesis in polluted wild animals is affected by this compound.
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Affiliation(s)
- Takeshi Yamazaki
- Faculty of Integrated Arts and Sciences, Hiroshima University, 1-7-1 Kagamiyama 739-8524, Japan.
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Nakatsu Y, Kotake Y, Komasaka K, Hakozaki H, Taguchi R, Kume T, Akaike A, Ohta S. Glutamate Excitotoxicity Is Involved in Cell Death Caused by Tributyltin in Cultured Rat Cortical Neurons. Toxicol Sci 2005; 89:235-42. [PMID: 16207939 DOI: 10.1093/toxsci/kfj007] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Tributyltin, an endocrine-disrupting chemical, has been used as a heat stabilizer, agricultural pesticide, and component of antifouling paints. In this study, the neurotoxicity of tributyltin was investigated in cultured rat cortical neurons. Tributyltin caused marked time- and dose-dependent increases in the number of trypan blue-stained cells. Measurement of extracellular glutamate concentration showed that glutamate release was induced by tributyltin. Application of the glutamate receptor antagonists MK-801 and CNQX decreased the neurotoxicity. These results suggest that released glutamate and glutamate receptors are involved in tributyltin toxicity. Next, we examined whether various factors, believed to be involved in glutamate excitotoxicity also influence tributyltin toxicity. Cell death induced by tributyltin was found to be reduced by alpha-tocopherol (a membrane-permeable antioxidant), SB202190 (a p38 mitogen-activated protein kinase inhibitor), and U-0126 (an extracellular signal-regulated protein kinase kinase inhibitor). MK-801 and CNQX decreased the phosphorylation of ERK, but not that of p38. A caspase-3 inhibitor had no effect on tributyltin toxicity, and tributyltin did not change the nuclear morphology. These results suggest that the glutamate excitotoxicity caused by tributyltin is unrelated to apoptosis. In conclusion, we demonstrated that tributyltin induced glutamate release and subsequent activation of glutamate receptors, leading to neuronal death. We propose two independent neuronal death pathways by tributyltin; one is glutamate receptor-dependent cell death via ERK phosphorylation, and the other may be glutamate receptor-independent cell death via p38 activation.
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Affiliation(s)
- Yusuke Nakatsu
- Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima, 734-8551, Japan
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Mulholland PJ, Stepanyan TD, Self RL, Hensley AK, Harris BR, Kowalski A, Littleton JM, Prendergast MA. Corticosterone and dexamethasone potentiate cytotoxicity associated with oxygen-glucose deprivation in organotypic cerebellar slice cultures. Neuroscience 2005; 136:259-67. [PMID: 16182452 DOI: 10.1016/j.neuroscience.2005.07.043] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2005] [Revised: 07/15/2005] [Accepted: 07/19/2005] [Indexed: 11/17/2022]
Abstract
Many patients display elevated levels of serum cortisol following acute ischemic stroke. Given that glucocorticoids may potentiate some forms of insult, these studies examined the effects of corticosterone or dexamethasone exposure on cytotoxicity following oxygen-glucose deprivation in the cerebellum, a brain region susceptible to stroke. In organotypic cerebellar slice cultures prepared from neonatal rat pups, 90-min of oxygen-glucose deprivation at 15 days in vitro resulted in significant cytotoxicity at 24-, 48-, and 72-h post-oxygen-glucose deprivation, as measured by uptake of propidium iodide. Exposure of cultures following oxygen-glucose deprivation to the antioxidant trolox (500 microM), but not to the glucocorticoid receptor antagonist RU486 (10 microM), completely blocked oxygen-glucose deprivation-induced cytotoxicity. Corticosterone (1 microM) or dexamethasone (10 microM) exposure alone did not significantly increase propidium iodide uptake above levels observed in control cultures. However, corticosterone or dexamethasone exposure after oxygen-glucose deprivation potentiated oxygen-glucose deprivation-mediated propidium iodide uptake at each time point. Trolox, as well as RU486, co-exposure of cultures to corticosterone or dexamethasone after oxygen-glucose deprivation abolished all cytotoxicity. In conclusion, these data demonstrated that glucocorticoid exposure modulated oxygen-glucose deprivation-mediated propidium iodide uptake, which likely involved glucocorticoid receptor activation and pro-oxidant effects.
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Affiliation(s)
- P J Mulholland
- Department of Psychology, University of Kentucky, 115 Kastle Hall, Lexington, KY 40506-0044, USA.
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Opinion of the Scientific Panel on contaminants in the food chain [CONTAM] to assess the health risks to consumers associated with exposure to organotins in foodstuffs. EFSA J 2004. [DOI: 10.2903/j.efsa.2004.102] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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Abstract
Organotin compounds have a broad range of applications. While dialkyltin compounds are used primarily as stabilizers for plastics, trisubstituted organotins are mainly used as biocides e.g., as an active ingredient of marine antifouling paints for boats and ships. Since a number of organotin compounds have been demonstrated to be toxic, there is increasing concern that their widespread use may cause adverse effects within environmental and biological systems. Besides carcinogenic and neurotoxic effects, as well as effects on the reproductive system, the most obvious mammalian effects of both various di- and trisubstituted organotins were found on the immune system. Exposure of humans to organotin compounds can take place through consumption of contaminated fish and seafood. In human liver samples, mainly dibutyltin, the metabolite of tributyltin, could be detected indicating that organotin compounds are bioavailable after dietary exposure. The objective of this short review is to present various toxicokinetic aspects of organotin compounds in more detail. While several studies using in vitro systems investigated their metabolism especially by the monooxygenase system, various aspects of absorption, distribution, metabolism, and excretion (ADME) pathways of different organotin compounds were described by data obtained from several studies with laboratory animals. However, most of these studies were not conducted as full ADME studies but dealt only with some of these aspects. Therefore, for definitive conclusions in some cases, additional information is requested. By reviewing and updating the current literature consideration was given preferentially to those organotin compounds which have relevance with respect to human exposure and/or toxicological effects.
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Affiliation(s)
- Klaus E Appel
- Federal Institute for Risk Assessment, Berlin, Germany
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Kim JM, Lee P, Son D, Kim H, Kim SY. Falcarindiol inhibits nitric oxide-mediated neuronal death in lipopolysaccharide-treated organotypic hippocampal cultures. Neuroreport 2003; 14:1941-4. [PMID: 14561925 DOI: 10.1097/00001756-200310270-00012] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Excessive nitric oxide (NO) release from activated microglia has a predominant role in neuronal death. This study investigated the effect of falcarindiol, which was isolated from Cnidium officinale Makino, on the NO-mediated neuronal death in lipopolysaccharide (LPS)-treated organotypic hippocampal cultures. Falcarindiol dose-dependently reduced inducible NO synthase (iNOS)-mediated NO production without cytotoxic effects on LPS-activated BV-2 and microglia. Predictably, falcarindiol inhibited neuronal death by reducing NO production in the LPS-treated organotypic hippocampal cultures. N-monomethyl-L-arginine (NMMA), an iNOS inhibitor, also inhibited neuronal death at 500 microM. In contrast, massive neuronal death was induced by excessive NO production in the LPS-treated alone cultures. These results suggest that excessive NO production plays an important role in the neurotoxic effect, and falcarindiol is a potential inhibitor in NO-mediated neuronal death.
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Affiliation(s)
- Jeong Min Kim
- Department of Herbal Pharmacology, Graduate School of East-West Medical Science, Kyunghee University, Seoul, Korea
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36
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Tiano L, Fedeli D, Santoni G, Davies I, Falcioni G. Effect of tributyltin on trout blood cells: changes in mitochondrial morphology and functionality. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1640:105-12. [PMID: 12729919 DOI: 10.1016/s0167-4889(03)00025-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The aquatic environment is the largest sink for the highly toxic organotin compounds, particularly as one of the main sources is the direct release of organotins from marine antifouling paints. The aim of this study was to investigate the mitochondrial toxicity and proapoptotic activity of tributyltin chloride (TBTC) in teleost leukocytes and nucleated erythrocytes, by means of electron microscopy investigation and mitochondrial membrane potential evaluation, in order to provide an early indicator of aquatic environmental pollution. Erythrocytes and leukocytes were obtained from an inbred strain of rainbow trout (Oncorhynchus mykiss). Transmission electronic micrographs of trout red blood cells (RBC) incubated in the presence of TBTC at 1 and 5 microM for 60 min showed remarkable mitochondrial morphological changes. TBTC-mediated toxicity involved alteration of the cristae ultrastructure and mitochondrial swelling, in a dose-dependent manner. Both erythrocytes and leukocytes displayed a consistent drop in mitochondrial membrane potential following TBTC exposure at concentrations >1 microM. The proapoptotic effect of TBTC on fish blood cells, and involvement of mitochondrial pathways was also investigated by verifying the release of cytochrome c, activation of caspase-3 and the presence of "DNA laddering". Although mitochondrial activity was much more strongly affected in erythrocytes, leukocytes incubated in the presence of TBTC showed the characteristic features of apoptosis after only 1 h of incubation. Longer exposures, up to 12 h, were required to trigger an apoptotic response in erythrocytes.
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Affiliation(s)
- Luca Tiano
- Department of Biology MCA, University of Camerino, Camerino (MC), Italy.
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Kurita R, Hayashi K, Torimitsu K, Niwa O. Continuous Measurement of Glutamate and Hydrogen Peroxide Using a Microfabricated Biosensor for Studying the Neurotoxicity of Tributyltin. ANAL SCI 2003; 19:1581-5. [PMID: 14696918 DOI: 10.2116/analsci.19.1581] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We first measured the effects of trace levels of an endocrine disruptor, tributyltin (TBT), on the secretion response from nerve cells using a microfabricated biosensor designed for the continuous measurement of L-glutamate and hydrogen peroxide. We observed higher and long-lasting glutamate and hydrogen peroxide concentrations from the cells when cultured rat cortical neurons were exposed to TBT. Glutamate and hydrogen peroxide release was induced even when we reduced the TBT concentration to 10 nM. This concentration is about two orders of magnitude lower than the concentration that induced apoptosis-like cell death. We also report on the effects of NMDA and non-NMDA receptor antagonists, which can help us to understand the mechanism of TBT neurotoxicity.
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Affiliation(s)
- Ryoji Kurita
- NTT Advanced Technology, 3-1 Morinosato-Wakamiva, Atsugi, Kanagawa 243-0124, Japan
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Lavastre V, Girard D. Tributyltin induces human neutrophil apoptosis and selective degradation of cytoskeletal proteins by caspases. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2002; 65:1013-1024. [PMID: 12133234 DOI: 10.1080/00984100290071270] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Tributyltin (TBT) has frequently been used as a pesticide and in biocidal paints for marine vessels, leading to its presence in the environment. Although TBT was recently found to induce apoptosis in different immune cells, by a mechanism that is not fully established, its effect on neutrophils is not known. In this study, it was found that TBT induced apoptosis in human neutrophils as assessed by cytology, flow cytometry, and degradation of the microfilament-associated protein gelsolin. Furthermore, data showed that TBT induced neutrophil apoptosis by a caspase-dependent mechanism, since addition of z-Val-Ala-Asp(MOe)-CH(2)F (z-VAD-FMK) in the culture prevented the effect of TBT. It was also found that the cytoskeletal proteins gelsolin, paxillin, and vimentin, but not vinculin, were degraded by TBT via caspases, as assessed by immunoblotting. Data indicate that gelsolin, paxillin, and vimentin are three caspase substrates involved in both spontaneous and TBT-induced neutrophil apoptosis. Cells were not necrotic as assessed by trypan blue dye exclusion, and this is in agreement with the absence of vinculin degradation. Evidence indicates that TBT-induced fragmentation of cytoskeletal proteins via caspases is a process that is tightly regulated.
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Affiliation(s)
- Valérie Lavastre
- INRS-Institut Armand-Frappier/Santéhumaine, Universitédu Québec, Pointe-Claire, Québec, Canada
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Kim JA, Mitsukawa K, Yamada MK, Nishiyama N, Matsuki N, Ikegaya Y. Cytoskeleton disruption causes apoptotic degeneration of dentate granule cells in hippocampal slice cultures. Neuropharmacology 2002; 42:1109-18. [PMID: 12128012 DOI: 10.1016/s0028-3908(02)00052-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Colchicine, a potent microtubule-depolymerizing agent, is well known to selectively kill dentate granule cells in the hippocampal formation in vivo. Using organotypic cultures of rat entorhino-hippocampal slices, we confirmed that in vitro exposure to 1 microM and 10 microM of colchicine reproduced a specific degeneration of the granule cells after 24 h. Similar results were obtained with other types of microtubule-disrupting agents, i.e., nocodazole, vinblastine, and Taxol. Interestingly, the actin-depolymerizing agents cytochalasin D and latrunculin A also elicited selective neurotoxicity in the dentate gyrus without affecting survival of hippocampal pyramidal cells. The selective pattern of degeneration was observable 24 h after a brief treatment with the toxins as short as 5 min, but this delayed neuronal death was unlikely to be a result of excitotoxicity because it was virtually unaffected by glutamate receptor antagonists, tetrodotoxin, or extracellular Ca(2+)-free conditions. The damaged tissues contained a large number of TUNEL-positive neurons and exhibited an increased level in caspase-3-like activity, suggesting that cytoskeleton disruption triggers an apoptosis-like process in dentate granule cells. Thus, this study may provide a basis for understanding the distinctive mechanism that supports granule cell survival.
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Affiliation(s)
- Jeong-Ah Kim
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Abstract
Tributyltin oxide (TBTO) is a commonly used biocide. The purpose of this study is to correlate the toxicity of TBTO with the alterations of brain neurotransmitters and ATPases. TBTO was given by stomach tube to rats at either 37.5 or 75 mg x kg (-1)for 3 consecutive days. Nervous signs appeared in treated animals and the mortality reached 12 and 30%, respectively. The levels of brain dopamine, norepinephrine and serotonin decreased in a dose-dependent manner. The activities of brain total ATPase, Mg (2+)-ATPase and Na (+)/K (+)- ATPase were suppressed. The activity of Na (+)/K (+)- ATPase was more severely affected than that of Mg (2+)-ATPase. Histopathological changes in brain included hyperaemia, focal haemorrhages in vacuolated myelinated fibres, chromatolysis, or complete necrosis of neurons, degenerative changes, or complete absence of purkinje cells in the cerebellum.
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Affiliation(s)
- Hesham S Elsabbagh
- Departments of Toxicology and Forensic Medicine and Biochemistry, Faculty of Veterinary Medicine, Cairo University, Egypt
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Oku N, Ueda Y, Yamakawa S, Kunimoto M. A New Bioassay of Environmental Chemicals Based on Their Effects on Tumor Cell Invasion. ACTA ACUST UNITED AC 2002. [DOI: 10.1248/jhs.48.310] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Naoto Oku
- School of Pharmaceutical Sciences, University of Shizuoka
| | - Yoko Ueda
- School of Pharmaceutical Sciences, University of Shizuoka
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Mizuhashi S, Ikegaya Y, Nishiyama N, Matsuki N. Cortical astrocytes exposed to tributyltin undergo morphological changes in vitro. JAPANESE JOURNAL OF PHARMACOLOGY 2000; 84:339-46. [PMID: 11138736 DOI: 10.1254/jjp.84.339] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We investigated the effect of tributyltin (TBT), an endocrine-disrupting chemical, on the morphology and viability of cultured rat cortical astrocytes. Cultured astrocytes exhibited smooth and planiform morphology under normal conditions. Following exposure to TBT, however, they showed rapid morphological changes that are characterized by asteriated cell bodies and process formation in a time- and concentration-dependent manner. Higher concentrations of TBT produced progressive cell death of the astrocytes. In serum-free medium, TBT at a concentration as low as 200 nM induced the stellation. Pharmacological studies revealed that the morphological changes were alleviated by application of diverse free radical scavengers or antioxidants such as catalase, superoxide dismutase, Trolox, ascorbic acid and N-acetyl-L-cysteine, suggesting that TBT-induced stellation is caused by oxidative stress involving free radicals, particularly reactive oxygen species. Furthermore, we found that the astrocyte stellation was abolished by treatment with inhibitors of phospholipase C, mitogen-activated protein kinase kinase or tyrosine phosphatase. The data suggest that TBT causes the stellation through intracellular signaling cascades rather than its non-specific toxicity. These findings provide an important insight for reconciling the problems in assumed aversive actions of this environmental pollutant for mammals.
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Affiliation(s)
- S Mizuhashi
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Japan
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