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Denuzière A, Ghersi-Egea JF. Cerebral concentration and toxicity of endocrine disrupting chemicals: The implication of blood-brain interfaces. Neurotoxicology 2022; 91:100-118. [DOI: 10.1016/j.neuro.2022.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 04/06/2022] [Accepted: 04/12/2022] [Indexed: 11/28/2022]
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Hanano A, Shaban M, Murphy DJ. Functional involvement of caleosin/peroxygenase PdPXG4 in the accumulation of date palm leaf lipid droplets after exposure to dioxins. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 281:116966. [PMID: 33799204 DOI: 10.1016/j.envpol.2021.116966] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 03/03/2021] [Accepted: 03/15/2021] [Indexed: 06/12/2023]
Abstract
Dioxins are highly injurious environmental pollutants with proven toxicological effects on both animals and humans, but to date their effects on plants still need to be studied in detail. We identified a dioxin-inducible caleosin/peroxygenase isoform, PdPXG4, that is mostly expressed in leaves of date palm seedlings and exhibits a specific reductase activity towards the 13-hydroperoxide of C18:2 and C18:3 (HpODE and HpOTrE, respectively). After exposure to TCDD, lipid droplets (LDs) isolated from TCDD-exposed leaves were about 6.5-15.7-fold more active in metabolizing 13-HpOTrE compared with those isolated from non-exposed leaves. A characteristic spectrum of leaf dioxin-responsive oxylipins (LDROXYL) was detected in dioxin-exposed seedlings. Of particular importance, a group of these oxylipins, referred to as Class I, comprising six congeners of hydroxides fatty acids derived from C18:2 and C18:3, was exclusively found in leaves after exposure to TCDD. The TCDD-induced oxylipin pattern was confirmed in vitro using terbufos, a typical inhibitor towards the PdPXG4 peroxygenase activity. Of particular interest, the response of terbufos-pretreated protoplasts to TCDD was drastically reduced. Together, these findings suggest that PdPXG4 is implicated in the establishment of a dioxin-specific oxylipin signature in date palm leaves soon after their exposure to these pollutants.
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Affiliation(s)
- Abdulsamie Hanano
- Department of Molecular Biology and Biotechnology, Atomic Energy Commission of Syria (AECS), Damascus, Syria.
| | - Mouhnad Shaban
- Department of Molecular Biology and Biotechnology, Atomic Energy Commission of Syria (AECS), Damascus, Syria.
| | - Denis J Murphy
- Genomics and Computational Biology Research Group, University of South Wales, NP7 7ET, United Kingdom.
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Hattori Y, Takeda T, Fujii M, Taura J, Yamada H, Ishii Y. Attenuation of growth hormone production at the fetal stage is critical for dioxin-induced developmental disorder in rat offspring. Biochem Pharmacol 2021; 186:114495. [PMID: 33711284 DOI: 10.1016/j.bcp.2021.114495] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 02/22/2021] [Accepted: 02/24/2021] [Indexed: 02/08/2023]
Abstract
Although dioxins and related chemicals have been suspected to disrupt child development, their toxic mechanism remains poorly understood. Our previous studies in rat fetuses revealed that maternal exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a highly-toxic dioxin, suppresses fetal synthesis of pituitary growth hormone (GH) that is essential for development. This study examined the hypothesis that attenuating GH expression in fetuses triggers developmental disorders. Treating pregnant rats with 1 μg/kg TCDD reduced the circulating level of GH and its downstream factor, insulin-like growth factor-1 (IGF-1), in the offspring only during the fetal and early neonatal stages. Although maternal TCDD exposure resulted in low body weight and length at babyhood and defects in the learning and memory ability at adulthood, GH supplementation in TCDD-exposed fetuses restored or tended to restore the defects including IGF-1 downregulation. Moreover, maternal TCDD exposure decreased the number of GH-positive cells during the fetal/neonatal stage. A microarray analysis showed that TCDD reduced the expression of death-associated protein-like 1 (DAPL1), a cell cycle-dependent proliferation regulator, in the fetal pituitary gland. In addition, TCDD treatment attenuated proliferating cells and cyclin mRNA expression in the fetal pituitary gland. Aryl hydrocarbon receptor (AHR)-knockout fetuses were insensitive to TCDD treatment, indicating that the TCDD-induced reduction in DAPL1 and GH mRNAs expression was due to AHR activation. Finally, DAPL1 knockdown suppressed GH and cyclin D2 expression in fetal pituitary cells. These results provide a novel evidence that dioxin suppresses GH-producing cell proliferation and GH synthesis due to partly targeting DAPL1, thereby impairing offspring development.
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Affiliation(s)
- Yukiko Hattori
- Laboratory of Molecular Life Sciences, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Tomoki Takeda
- Laboratory of Molecular Life Sciences, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Misaki Fujii
- Laboratory of Molecular Life Sciences, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Junki Taura
- Laboratory of Molecular Life Sciences, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Hideyuki Yamada
- Laboratory of Molecular Life Sciences, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Yuji Ishii
- Laboratory of Molecular Life Sciences, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan; Division of Pharmaceutical Cell Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.
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Takeda T, Fujii M, Izumoto W, Hattori Y, Matsushita T, Yamada H, Ishii Y. Gestational dioxin exposure suppresses prolactin-stimulated nursing in lactating dam rats to impair development of postnatal offspring. Biochem Pharmacol 2020; 178:114106. [PMID: 32569627 DOI: 10.1016/j.bcp.2020.114106] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/15/2020] [Accepted: 06/17/2020] [Indexed: 12/11/2022]
Abstract
A number of epidemiological studies have implicated environmental chemicals including dioxins in the induction of negative effects on child development. To clarify the underlying mechanisms, almost all toxicologists have concentrated on effects on the offspring themselves. We examined an alternative hypothesis that gestational exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a highly-toxic dioxin, targets factors related to maternal childcare to disturb offspring development. Oral administration of TCDD (1 µg/kg) to pregnant rats on gestational day 15 suppressed maternal licking behavior, a nursing behavior, and mammary gland maturation during the lactational stage, as well as the body weight and short-term memory of postnatal offspring. In support of these findings, maternal production of prolactin, a pituitary hormone essential for nursing including milk production, was decreased during the same period. Intracerebroventricular infusion of prolactin to dioxin-exposed dams restored or tended to restore many of the above defects observed both in mothers and offspring. The TCDD-dependent defects in maternal nursing behaviors can be due to a direct action on aryl hydrocarbon receptor (AHR) of lactating dams, because they did not emerge in AHR-knockout dams or control dams with TCDD-exposed offspring. Further examinations revealed that TCDD induces transforming growth factor β1 expression, which suppresses prolactin-producing cell proliferation, in a nursing period-specific manner. In agreement with this, the number of prolactin-positive cells in nursing dams was decreased by TCDD. These results provide novel evidence that gestational dioxin exposure attenuates prolactin-stimulated nursing in lactating dams to impair offspring development, and that immaturity of prolactin-producing cells can contribute to them.
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Affiliation(s)
- Tomoki Takeda
- Laboratory of Molecular Life Sciences, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Misaki Fujii
- Laboratory of Molecular Life Sciences, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Waka Izumoto
- Laboratory of Molecular Life Sciences, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Yukiko Hattori
- Laboratory of Molecular Life Sciences, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Takeshi Matsushita
- Laboratory of Molecular Life Sciences, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Hideyuki Yamada
- Laboratory of Molecular Life Sciences, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Yuji Ishii
- Laboratory of Molecular Life Sciences, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan; Division of Pharmaceutical Cell Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.
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Hanano A, Almousally I, Shaban M. Exposure of Aspergillus flavus NRRL 3357 to the Environmental Toxin, 2,3,7,8-Tetrachlorinated Dibenzo- p-Dioxin, Results in a Hyper Aflatoxicogenic Phenotype: A Possible Role for Caleosin/Peroxygenase (AfPXG). Front Microbiol 2019; 10:2338. [PMID: 31681203 PMCID: PMC6803392 DOI: 10.3389/fmicb.2019.02338] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 09/25/2019] [Indexed: 12/19/2022] Open
Abstract
Aflatoxins (AFs) as potent food contaminants are highly detrimental to human and animal health. The production of such biological toxins is influenced by environmental factors including pollutants, such as dioxins. Here, we report the biological feedback of an active AF-producer strain of A. flavus upon in vitro exposure to the most toxic congener of dioxins, the 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (TCDD). The phenotype of TCDD-exposed A. flavus was typified by a severe limitation in vegetative growth, activation of conidia formation and a significant boost in AF production. Furthermore, the level of reactive oxygen species (ROS) in fungal protoplast was increased (3.1- to 3.8-fold) in response to TCDD exposure at 10 and 50 ng mL-1, respectively. In parallel, superoxide dismutase (SOD) and catalase (CAT) activities were, respectively, increased by a factor of 2 and 3. In contrast to controls, transcript, protein and enzymatic activity of caleosin/peroxygenase (AfPXG) was also significantly induced in TCDD-exposed fungi. Subsequently, fungal cells accumulated fivefold more lipid droplets (LDs) than controls. Moreover, the TCDD-exposed fungi exhibited twofold higher levels of AFB1. Interestingly, TCDD-induced hyperaflatoxicogenicity was drastically abolished in the AfPXG-silencing strain of A. flavus, suggesting a role for AfPXG in fungal response to TCDD. Finally, TCDD-exposed fungi showed an increased in vitro virulence in terms of sporulation and AF production. The data highlight the possible effects of dioxin on aflatoxicogenicity of A. flavus and suggest therefore that attention should be paid in particular to the potential consequences of climate change on global food safety.
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Affiliation(s)
- Abdulsamie Hanano
- Department of Molecular Biology and Biotechnology, Atomic Energy Commission of Syria, Damascus, Syria
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Identification of a dioxin-responsive oxylipin signature in roots of date palm: involvement of a 9-hydroperoxide fatty acid reductase, caleosin/peroxygenase PdPXG2. Sci Rep 2018; 8:13181. [PMID: 30181584 PMCID: PMC6123484 DOI: 10.1038/s41598-018-31342-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 07/17/2018] [Indexed: 01/02/2023] Open
Abstract
Dioxins are highly hazardous pollutants that have well characterized impacts on both animal and human health. However, the biological effects of dioxins on plants have yet to be described in detail. Here we describe a dioxin-inducible caleosin/peroxygenase isoform, PdPXG2, that is mainly expressed in the apical zone of date palm roots and specifically reduces 9-hydroperoxide fatty acids. A characteristic spectrum of 18 dioxin-responsive oxylipin (DROXYL) congeners was also detected in date palm roots after exposure to dioxin. Of particular interest, six oxylipins, mostly hydroxy fatty acids, were exclusively formed in response to TCDD. The DROXYL signature was evaluated in planta and validated in vitro using a specific inhibitor of PdPXG2 in a root-protoplast system. Comparative analysis of root suberin showed that levels of certain monomers, especially the mono-epoxides and tri-hydroxides of C16:3 and C18:3, were significantly increased after exposure to TCDD. Specific inhibition of PdPXG2 activity revealed a positive linear relationship between deposition of suberin in roots and their permeability to TCDD. The results highlight the involvement of this peroxygenase in the plant response to dioxin and suggest the use of dioxin-responsive oxylipin signatures as biomarkers for plant exposure to this important class of xenobiotic contaminants.
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The Aryl Hydrocarbon Receptor and the Nervous System. Int J Mol Sci 2018; 19:ijms19092504. [PMID: 30149528 PMCID: PMC6163841 DOI: 10.3390/ijms19092504] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 08/17/2018] [Accepted: 08/21/2018] [Indexed: 12/12/2022] Open
Abstract
The aryl hydrocarbon receptor (or AhR) is a cytoplasmic receptor of pollutants. It translocates into the nucleus upon binding to its ligands, and forms a heterodimer with ARNT (AhR nuclear translocator). The heterodimer is a transcription factor, which regulates the transcription of xenobiotic metabolizing enzymes. Expressed in many cells in vertebrates, it is mostly present in neuronal cell types in invertebrates, where it regulates dendritic morphology or feeding behavior. Surprisingly, few investigations have been conducted to unravel the function of the AhR in the central or peripheral nervous systems of vertebrates. In this review, we will present how the AhR regulates neural functions in both invertebrates and vertebrates as deduced mainly from the effects of xenobiotics. We will introduce some of the molecular mechanisms triggered by the well-known AhR ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), which impact on neuronal proliferation, differentiation, and survival. Finally, we will point out the common features found in mice that are exposed to pollutants, and in AhR knockout mice.
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The effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin on the development and function of the blood–brain barrier. Neurotoxicology 2016; 52:64-71. [DOI: 10.1016/j.neuro.2015.11.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 11/05/2015] [Accepted: 11/09/2015] [Indexed: 01/03/2023]
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Hanano A, Almousally I, Shaban M, Moursel N, Shahadeh A, Alhajji E. Differential tissue accumulation of 2,3,7,8-Tetrachlorinated dibenzo-p-dioxin in Arabidopsis thaliana affects plant chronology, lipid metabolism and seed yield. BMC PLANT BIOLOGY 2015; 15:193. [PMID: 26260741 PMCID: PMC4531507 DOI: 10.1186/s12870-015-0583-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 07/29/2015] [Indexed: 05/04/2023]
Abstract
BACKGROUND Dioxins are one of the most toxic groups of persistent organic pollutants. Their biotransmission through the food chain constitutes a potential risk for human health. Plants as principal actors in the food chain can play a determinant role in removing dioxins from the environment. Due to the lack of data on dioxin/plant research, this study sets out to determine few responsive reactions adopted by Arabidopsis plant towards 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the most toxic congener of dioxins. RESULTS Using a high resolution gas chromatography/mass spectrometry, we demonstrated that Arabidopsis plant uptakes TCDD by the roots and accumulates it in the vegetative parts in a tissue-specific manner. TCDD mainly accumulated in rosette leaves and mature seeds and less in stem, flowers and immature siliques. Moreover, we observed that plants exposed to high doses of TCDD exhibited a delay in flowering and yielded fewer seeds of a reduced oil content with a low vitality. A particular focus on the plant fatty acid metabolism showed that TCDD caused a significant reduction in C18-unsaturated fatty acid level in plant tissues. Simultaneously, TCDD induced the expression of 9-LOX and 13-LOX genes and the formation of their corresponding hydroperoxides, 9- and 13-HPOD as well as 9- or 13-HPOT, derived from linoleic and linolenic acids, respectively. CONCLUSIONS The current work highlights a side of toxicological effects resulting in the administration of 2,3,7,8-TCDD on the Arabidopsis plant. Similarly to animals, it seems that plants may accumulate TCDD in their lipids by involving few of the FA-metabolizing enzymes for sculpting a specific oxylipins "signature" typified to plant TCDD-tolerance. Together, our results uncover novel responses of Arabidopsis to dioxin, possibly emerging to overcome its toxicity.
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Affiliation(s)
- Abdulsamie Hanano
- Atomic Energy Commission of Syria (AECS), B.P. Box 6091, Damascus, Syria.
- Department of Molecular Biology and Biotechnology, Atomic Energy Commission of Syria (AECS), P.O. Box 6091, Damascus, Syria.
| | - Ibrahem Almousally
- Atomic Energy Commission of Syria (AECS), B.P. Box 6091, Damascus, Syria.
- Department of Molecular Biology and Biotechnology, Atomic Energy Commission of Syria (AECS), P.O. Box 6091, Damascus, Syria.
| | - Mouhnad Shaban
- Atomic Energy Commission of Syria (AECS), B.P. Box 6091, Damascus, Syria.
- Department of Molecular Biology and Biotechnology, Atomic Energy Commission of Syria (AECS), P.O. Box 6091, Damascus, Syria.
| | - Nour Moursel
- Atomic Energy Commission of Syria (AECS), B.P. Box 6091, Damascus, Syria.
- Department of Molecular Biology and Biotechnology, Atomic Energy Commission of Syria (AECS), P.O. Box 6091, Damascus, Syria.
| | - AbdAlbaset Shahadeh
- Atomic Energy Commission of Syria (AECS), B.P. Box 6091, Damascus, Syria.
- Department of Chemistry, Atomic Energy Commission of Syria (AECS), P.O. Box 6091, Damascus, Syria.
| | - Eskander Alhajji
- Atomic Energy Commission of Syria (AECS), B.P. Box 6091, Damascus, Syria.
- Department of Protection and Safety, Atomic Energy Commission of Syria (AECS), P.O. Box 6091, Damascus, Syria.
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Rosińczuk J, Całkosiński I. Effect of tocopherol and acetylsalicylic acid on the biochemical indices of blood in dioxin-exposed rats. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2015; 40:1-11. [PMID: 26056971 DOI: 10.1016/j.etap.2015.04.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 04/21/2015] [Accepted: 04/28/2015] [Indexed: 06/04/2023]
Abstract
New sources of dioxins and increased dioxin concentrations in the environment, coupled with their increased bioavailability along the food chain and accumulation in adipose tissues, contribute to various adverse long-term biological effects. The purpose of the study was to determine whether tocopherol protects the CNS by decreasing the pro-inflammatory influence of free radicals generated by TCDD; whether acetylsalicylic acid inhibits the production of inflammatory mediators; and whether the combined administration of tocopherol and acetylsalicylic acid to TCDD-exposed rats has a potential CNS-protective effect. The study included 117 rats divided into 8 groups: 75 female and 12 male Buffalo rats aged 8-10 weeks, weighing 140-160 g; as well as 30 female rats aged 6 weeks and weighing 120 g, which were the offspring of females from each study group. In the experiment, the following substances were used: 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), dosed at 5 μg/kg BW and 12.5 μg/kg BW, diluted in a 1% DMSO solution at the concentration of 1 μg/ml; α-tocopherol acetate, dosed at 30 mg/kg BW, in 0.2 ml of oil solution; and acetylsalicylic acid, 50mg/kg BW, suspended in 0.5 ml of starch solution, administered orally using a feeding tube. Pleurisy was induced by an injection of 0.15 ml of 1% carrageenin solution. The use of tocopherol reduces the adverse effects of the inflammatory reaction induced by TCDD. Administering tocopherol improves protein metabolism by reducing protein catabolism, and raises γ-globulin fraction levels. Combined acetylsalicylic acid and tocopherol suppress catabolic processes accompanying inflammation.
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Affiliation(s)
- Joanna Rosińczuk
- Department of Nervous System Diseases, The Faculty of Health Science, Wroclaw Medical University, Bartla 5 Street, 51-618 Wrocław, Poland.
| | - Ireneusz Całkosiński
- Department of Nervous System Diseases, The Faculty of Health Science, Wroclaw Medical University, Bartla 5 Street, 51-618 Wrocław, Poland.
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Histopathological, ultrastructural, and immunohistochemical assessment of hippocampus structures of rats exposed to TCDD and high doses of tocopherol and acetylsalicylic acid. BIOMED RESEARCH INTERNATIONAL 2015; 2015:645603. [PMID: 25879034 PMCID: PMC4388018 DOI: 10.1155/2015/645603] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 03/13/2015] [Indexed: 12/21/2022]
Abstract
The effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on central nervous system consists of changing expression of estrogen receptors, whereas the result of chronic inflammatory reaction caused by dioxin is occurrence of destructive changes in various organs connected with disturbed metabolism of connective tissue and damage of cells. The aim of the study was to determine the effect of dioxins on function, ultrastructure, and cytological and histological structure of hippocampus, particularly on expression of estrogen receptors in central nervous system as well as to define protective influence of tocopherol (TCP) and acetylsalicylic acid (ASA) on the decrease in activity of proinflammatory effects in central nervous system. It was shown that TCDD contributes to destructive and inflammatory changes along with demyelization of myelin sheaths and atrophy of estrogen receptors in hippocampus. Dioxin contributes to atrophy of estrogen receptors in hippocampus, in which also destructive and inflammatory changes were found along with demyelination of myelin sheaths. Histopathological and ultrastructural image of hippocampus areas in rats, in which both TCP and ASA were used, is characterized by poorly expressed degenerative changes and smaller inflammatory reactivity. Using both TCP and ASA has a protective effect on functions of central nervous system.
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Takeda T, Yamamoto M, Himeno M, Takechi S, Yamaguchi T, Ishida T, Ishii Y, Yamada H. 2,3,7,8-tetrachlorodibenzo-p-dioxin potentially attenuates the gene expression of pituitary gonadotropin β-subunits in a fetal age-specific fashion: a comparative study using cultured pituitaries. J Toxicol Sci 2011; 36:221-9. [PMID: 21467749 DOI: 10.2131/jts.36.221] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Our previous studies have demonstrated that maternal exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) causes a reduction in gonadotropin biosynthesis in the fetal pituitary, resulting in the attenuated expression of steroidogenic proteins in the fetal gonads and the impairment of sexual behaviors in adulthood. However, the mechanism of the attenuation remains unknown. To address this issue, we investigated whether TCDD affects the pituitary production of gonadotropins, using cultured pituitary. In the absence of gonadotropin-releasing hormone (GnRH), a regulator of gonadotropin biosynthesis, TCDD did not affect the expression of gonadotropin mRNAs both in fetal and postnatal pituitaries. On the other hand, in the presence of GnRH, TCDD interfered with the synthesis of gonadotropin β-subunit mRNAs only in the fetal pituitary. A protein kinase C (PKC) activator (phorbol 12-myristate 13-acetate) and a PKA activator (8-bromoadenosine-3' 5'-cyclic monophosphate) induced the expression of gonadotropin mRNAs in the fetal pituitary. Among the subunits, only the induction of β-subunit was reduced by TCDD treatment. These results suggest that TCDD reduces gonadotropin biosynthesis via damage to GnRH-stimulated PKC and PKA signaling in a β-subunit- and fetal age-specific manner.
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Affiliation(s)
- Tomoki Takeda
- Graduate School of Pharmaceutical Sciences, Kyushu University, Japan
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Szabo DT, Diliberto JJ, Huwe JK, Birnbaum LS. Differences in Tissue Distribution of HBCD Alpha and Gamma between Adult and Developing Mice. Toxicol Sci 2011; 123:256-63. [DOI: 10.1093/toxsci/kfr161] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Lensu S, Tuomisto JT, Tuomisto J, Pohjanvirta R. Characterization of the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-provoked strong and rapid aversion to unfamiliar foodstuffs in rats. Toxicology 2011; 283:140-50. [DOI: 10.1016/j.tox.2011.03.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Accepted: 03/12/2011] [Indexed: 11/27/2022]
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