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Rana I, Rieswijk L, Steinmaus C, Zhang L. Formaldehyde and Brain Disorders: A Meta-Analysis and Bioinformatics Approach. Neurotox Res 2021; 39:924-948. [PMID: 33400181 PMCID: PMC8102312 DOI: 10.1007/s12640-020-00320-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 11/30/2020] [Accepted: 12/01/2020] [Indexed: 02/07/2023]
Abstract
While there is significant investigation and investment in brain and neurodegenerative disease research, current understanding of the etiologies of illnesses like Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and brain cancer remains limited. Environmental exposure to the pollutant formaldehyde, an emerging neurotoxin widely used in industry, is suspected to play a critical role in mediating these disorders, although findings are limited and inconsistent. Focusing on highly exposed groups, we performed a meta-analysis of human epidemiological studies of formaldehyde and neurodegenerative disease (N = 19) or brain tumors (N = 12). To assess the biological plausibility of observed associations, we then conducted a bioinformatics analysis using WikiPathways and the Comparative Toxicogenomics Database and identified candidate genes and pathways that may be related to these interactions. We reported the meta-relative risk (meta-RR) of ALS following high exposures to formaldehyde was increased by 78% (meta-RR = 1.78, 95% confidence interval, CI 1.20-2.65). Similarly, the meta-RR for brain cancer was increased by 71% (meta-RR = 1.71; 95% CI 1.07-2.73) among highly exposed individuals. Multiple sensitivity analyses did not reveal sources of heterogeneity or bias. Our bioinformatics analysis revealed that the oxidative stress genes superoxide dismutase (SOD1, SOD2) and the pro-inflammatory marker tumor necrosis factor (TNF) were identified as the top relevant genes, and the folate metabolism, vitamin B12 metabolism, and the ALS pathways were highly affected by formaldehyde and related to the most brain diseases of interest. Further inquiry revealed the two metabolic pathways are also intimately tied with the formaldehyde cycle. Overall, our bioinformatics analysis supports the link of formaldehyde exposure to ALS or brain tumor reported from our meta-analysis. This new multifactorial approach enabled us to both interrogate the robustness of the epidemiological data and identify genes and pathways that may be involved in these interactions, ultimately lending strong evidence and potential biological plausibility for the association between formaldehyde exposure and brain disease.
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Affiliation(s)
- Iemaan Rana
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA, USA
| | - Linda Rieswijk
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA, USA
- Institute of Data Science, Maastricht University, Maastricht, Netherlands
| | - Craig Steinmaus
- Division of Epidemiology and Biostatistics, School of Public Health, University of California Berkeley, Berkeley, CA, USA
| | - Luoping Zhang
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA, USA.
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Li X, Zhuang YY, Wu L, Xie M, Gu HF, Wang B, Tang XQ. Hydrogen Sulfide Ameliorates Cognitive Dysfunction in Formaldehyde-Exposed Rats: Involvement in the Upregulation of Brain-Derived Neurotrophic Factor. Neuropsychobiology 2020; 79:119-130. [PMID: 31550727 DOI: 10.1159/000501294] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 06/04/2019] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To investigate whether hydrogen sulfide (H2S) counteracts formaldehyde (FA)-induced cognitive defects and whether the underlying mechanism is involved in the upregulation of hippocampal brain-derived neurotrophic factor (BDNF) expression. METHODS The cognitive function of rats was evaluated by the Morris water maze (MWM) test and the novel object recognition test. The content of superoxide dismutase (SOD) and malondialdehyde (MDA) in the hippocampus were detected by enzyme-linked immunosorbent assay (ELISA). The neuronal apoptosis in the hippocampal CA1 region was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick-end (TUNEL) staining. The expression of the BDNF protein was detected by Western blot and immunohistochemistry. RESULTS We found that sodium hydrosulfide (NaHS, a donor of H2S) significantly reversed the impairment in the function of learning and memory in the MWM test and the novel objective recognition task induced by intracerebroventricular injection of FA. We also showed that NaHS significantly reduced the level of MDA, elevated the level of SOD, and decreased the amount of TUNEL-positive neurons in the hippocampus of FA-exposed rats. Moreover, NaHS markedly increased the expression of hippocampal BDNF in FA-exposed rats. CONCLUSIONS H2S attenuates FA-induced dysfunction of cognition and the underlying mechanism is involved in the reduction of hippocampal oxidative damage and apoptosis as well as upregulation of hippocampal BDNF.
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Affiliation(s)
- Xiang Li
- Department of Anesthesiology, The First Affiliated Hospital, University of South China, Hengyang, China
| | - Yuan-Yuan Zhuang
- Institute of Neurology, The First Affiliated Hospital, University of South China, Hengyang, China.,Key Laboratory for Cognitive Disorders and Neurodegenerative Diseases, Department of Physiology, Hengyang Medical College, University of South China, Hengyang, China
| | - Lei Wu
- Institute of Neurology, The First Affiliated Hospital, University of South China, Hengyang, China.,Key Laboratory for Cognitive Disorders and Neurodegenerative Diseases, Department of Physiology, Hengyang Medical College, University of South China, Hengyang, China
| | - Ming Xie
- Department of Neurology, The First Affiliated Hospital, University of South China, Hengyang, China
| | - Hong-Feng Gu
- Key Laboratory for Cognitive Disorders and Neurodegenerative Diseases, Department of Physiology, Hengyang Medical College, University of South China, Hengyang, China
| | - Bo Wang
- Department of Anesthesiology, The First Affiliated Hospital, University of South China, Hengyang, China
| | - Xiao-Qing Tang
- Department of Neurology, The First Affiliated Hospital, University of South China, Hengyang, China, .,Institute of Neurology, The First Affiliated Hospital, University of South China, Hengyang, China, .,Key Laboratory for Cognitive Disorders and Neurodegenerative Diseases, Department of Physiology, Hengyang Medical College, University of South China, Hengyang, China,
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Niu H, Xie R, Li L, Zhang X, Wei X, Deng J, Li Z. WITHDRAWN: Resveratrol partially prevents learning and memory deficits in rats exposed to gaseous formaldehyde. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2020:S1382-6689(20)30179-4. [PMID: 32976996 DOI: 10.1016/j.etap.2020.103503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 09/16/2020] [Accepted: 09/21/2020] [Indexed: 06/11/2023]
Abstract
This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.
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Affiliation(s)
- Huatao Niu
- Department of Neurosurgery, The Third Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650118, China
| | - Ran Xie
- Department of PET-CT, The Third Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650118, China
| | - Lanjiang Li
- College of Forensic Medicine, Kunming Medical University, Kunming, Yunnan 650031, China
| | - Xiang Zhang
- Experimental Demonstration Center, College of Basic Medical Science, Kunming Medical University, Kunming, Yunnan 650031, China
| | - Xiaohan Wei
- Department of Human Anatomy and Tissue Embryology, College of Basic Medical Science, Kunming Medical University, Kunming, Yunnan 650031, China
| | - Jie Deng
- Department of Human Anatomy and Tissue Embryology, College of Basic Medical Science, Kunming Medical University, Kunming, Yunnan 650031, China
| | - Zhongming Li
- Department of Human Anatomy and Tissue Embryology, College of Basic Medical Science, Kunming Medical University, Kunming, Yunnan 650031, China.
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Lee A, Arachchige BJ, Reed S, Henderson R, Aylward J, McCombe PA. Plasma from some patients with amyotrophic lateral sclerosis exhibits elevated formaldehyde levels. J Neurol Sci 2020; 409:116589. [DOI: 10.1016/j.jns.2019.116589] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 11/20/2019] [Accepted: 11/21/2019] [Indexed: 12/12/2022]
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Askar EM, Halloull NM. Formaldehyde-induced neurotoxicity in rat cerebellar cortex and possible protective effects of fatty acids from omega 3 and wheat germ oil supplement: a histopathological and biochemical study. J Histotechnol 2018. [DOI: 10.1080/01478885.2018.1458176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Eman Mohamed Askar
- Faculty of Human Medicine, Department of Histology and Cell Biology, Zagazig University, Zagazig, Egypt
| | - Noha Mohamed Halloull
- Faculty of Human Medicine, Department of Forensic Medicine and Clinical Toxicology, Zagazig University, Zagazig, Egypt
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Effect of hindlimb unloading on stereological parameters of the motor cortex and hippocampus in male rats. Neuroreport 2016; 27:1202-5. [PMID: 27607230 DOI: 10.1097/wnr.0000000000000675] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Hindlimb unloading (HU) can cause motion and cognition dysfunction, although its cellular and molecular mechanisms are not well understood. The aim of the present study was to determine the stereological parameters of the brain areas involved in motion (motor cortex) and spatial learning - memory (hippocampus) under an HU condition. Sixteen adult male rats, kept under a 12 : 12 h light-dark cycle, were divided into two groups of freely moving (n=8) and HU (n=8) rats. The volume of motor cortex and hippocampus, the numerical cell density of neurons in layers I, II-III, V, and VI of the motor cortex, the entire motor cortex as well as the primary motor cortex, and the numerical density of the CA1, CA3, and dentate gyrus subregions of the hippocampus were estimated. No significant differences were observed in the evaluated parameters. Our results thus indicated that motor cortical and hippocampal atrophy and cell loss may not necessarily be involved in the motion and spatial learning memory impairment in the rat.
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Ahmed HH, Morsy FA, El-Nabarawy SK, Ahmed MA, Ali NA. Lycopene: an effective neuroprotective option against neurodeterioration induced by formaldehyde inhalation. ACTA ACUST UNITED AC 2016. [DOI: 10.1007/s00580-016-2323-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Uluçam E, Bakar E. The effect of proanthocyanidin on formaldehyde-induced toxicity in rat testes. Turk J Med Sci 2016; 46:185-93. [PMID: 27511353 DOI: 10.3906/sag-1411-13] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 04/11/2015] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND/AIM This study investigated the effect of proanthocyanidin (PA) against formaldehyde (FA)-induced lipid peroxidation damage and morphological changes in rat testes. MATERIALS AND METHODS Twenty-one Wistar albino rats were randomized into 3 groups: control, FA, and FA + PA groups. Plasma and tissue malondialdehyde (MDA) and total sialic acid (TSA) levels were measured. Testes tissues were observed by light and electron microscopy. RESULTS TSA (plasma and tissue) levels decreased and MDA (plasma) significantly increased (P < 0.05) in rats treated with FA compared to the controls. Tissue MDA levels were not significantly different. Several necrotic changes were observed in testes tissues by light and electron microscopy. Disordering in epithelia of seminiferous tubules, vacuolization between germinal epithelium cells, and separated basement membranes were observed by light microscope. Immunopositivity in Leydig cells decreased in the FA group (P < 0.05). In the FA + PA group there were more immune Leydig cells reacting immune-positively than in the FA group (P < 0.05). Ultrastructurally, FA also caused disorganization and loss of mitochondrial cristae, and dilatation in endoplasmic reticulum in testes. CONCLUSION The results suggest that PA has a protective effect on FA toxicity in testes.
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Affiliation(s)
- Enis Uluçam
- Department of Anatomy, Faculty of Medicine, Trakya University, Edirne, Turkey
| | - Elvan Bakar
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Trakya University, Edirne, Turkey
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Bakar E, Ulucam E, Cerkezkayabekir A. Investigation of the protective effects of proanthocyanidin and vitamin E against the toxic effect caused by formaldehyde on the liver tissue. ENVIRONMENTAL TOXICOLOGY 2015; 30:1406-1415. [PMID: 24930571 DOI: 10.1002/tox.22010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 05/21/2014] [Accepted: 05/27/2014] [Indexed: 06/03/2023]
Abstract
We aimed to investigate of protective role of proanthocyanidin (PA) and vitamin E (vit E) against to toxic effect of formaldehyde (FA). Twenty-eight Wistar albino rats were divided into four groups: control group, rats treated with FA intraperitoneal (i.p.) (10 mg/kg), FA + vit E intragastric (i.g.) (30 mg/kg), and FA + PA i.g. (100 mg/kg). We assayed superoxide dismutase (SOD), glutathione peroxidase (Gpx), myeloperoxidase (MPO) activity and levels of malondialdehyde (MDA) and total sialic acid (TSA) in liver. Liver tissue was taken in order to morphological analysis and hepatocytes apoptosis using terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay immunostaining. SOD decreased in FA and increased in FA + vit E and FA + PA (p < 0.05). Gpx didn't change in FA and increased in FA + PA (p < 0.05). No significant variation between the groups was found in MPO activity. MDA increased only in FA and decreased in FA + vit E and FA+PA (p < 0.05). TSA didn't alter in FA and FA + vit E but decreased in FA + PA (p < 0.05). Degeneration in hepatocytes and endothelial cells, cytoplasm losses, vacuolization, picnotic nuclei, and mononuclear cell infiltration were identified in FA. Degeneration in chromatin material, membrane damage in mitochondria and losses in mitochondrial cristae in hepatocytes were observed in FA. We found that partially recovery in liver as a result of FA + vit E and FA + PA. We have concluded that long term use should be investigated for complete explanation of PA's protective effects on FA toxicity.
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Affiliation(s)
- Elvan Bakar
- Faculty of Pharmacy, Department of Pharmaceutical Technology, Trakya University, Edirne, Turkey
| | - Enis Ulucam
- Faculty of Medicine, Department of Anatomy, Trakya University, Edirne, Turkey
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Li G, Yang J, Ling S. Formaldehyde exposure alters miRNA expression profiles in the olfactory bulb. Inhal Toxicol 2015; 27:387-93. [PMID: 26161908 DOI: 10.3109/08958378.2015.1062580] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
It has been reported that inhaling formaldehyde (FA) causes damage to the central nervous system. However, it is unclear whether FA can disturb the function of the olfactory bulb. Using a microarray, we found that FA inhalation altered the miRNA expression profile. Functional enrichment analysis of the predicted targets of the changed miRNA showed that the enrichment canonical pathways and networks associated with cancer and transcriptional regulation. FA exposure disrupts miRNA expression profiles within the olfactory bulb.
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Affiliation(s)
- Guifa Li
- Institute of Neuroscience, Medical College, Zhejiang University , Hangzhou , P.R. China
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Li X, Zhang KY, Zhang P, Chen LX, Wang L, Xie M, Wang CY, Tang XQ. Hydrogen sulfide inhibits formaldehyde-induced endoplasmic reticulum stress in PC12 cells by upregulation of SIRT-1. PLoS One 2014; 9:e89856. [PMID: 24587076 PMCID: PMC3938548 DOI: 10.1371/journal.pone.0089856] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 01/23/2014] [Indexed: 12/29/2022] Open
Abstract
Background Formaldehyde (FA), a well-known environmental pollutant, has been classified as a neurotoxic molecule. Our recent data demonstrate that hydrogen sulfide (H2S), the third gaseous transmitter, has a protective effect on the neurotoxicity of FA. However, the exact mechanisms underlying this protection remain largely unknown. Endoplasmic reticulum (ER) stress has been implicated in the neurotoxicity of FA. Silent mating type information regulator 2 homolog 1 (SIRT-1), a histone deacetylases, has various biological activities, including the extension of lifespan, the modulation of ER stress, and the neuroprotective action. Objective We hypothesize that the protection of H2S against FA-induced neurotoxicity involves in inhibiting ER stress by upregulation of SIRT-1. The present study attempted to investigate the protective effect of H2S on FA-induced ER stress in PC12 cells and the contribution of SIRT-1 to the protection of H2S against FA-induced injuries, including ER stress, cytotoxicity and apoptosis. Principal Findings We found that exogenous application of sodium hydrosulfide (NaHS; an H2S donor) significantly attenuated FA-induced ER stress responses, including the upregulated levels of glucose-regulated protein 78, C/EBP homologous protein, and cleaved caspase-12 expression. We showed that NaHS upregulates the expression of SIRT-1 in PC12 cells. Moreover, the protective effects of H2S on FA-elicited ER stress, cytotoxicity and apoptosis were reversed by Sirtinol, a specific inhibitor of SIRT-1. Conclusion/Significance These data indicate that H2S exerts its protection against the neurotoxicity of FA through overcoming ER stress via upregulation of SIRT-1. Our findings provide novel insights into the protective mechanisms of H2S against FA-induced neurotoxicity.
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Affiliation(s)
- Xiang Li
- Department of Anesthesiology, the First Affiliated Hospital, University of South China, Hengyang, Hunan, P. R. China
- Department of Neurology, the First Affiliated Hospital, University of South China, Hengyang, Hunan, P. R. China
| | - Kai-Yan Zhang
- Department of Neurology, the First Affiliated Hospital, University of South China, Hengyang, Hunan, P. R. China
- Institute of Neuroscience, Medical College, University of South China, Hengyang, Hunan, P. R. China
| | - Ping Zhang
- Department of Neurology, Nanhua Affiliated Hospital, University of South China, Hengyang, Hunan, P. R. China
| | - Li-Xun Chen
- Department of Neurology, the First Affiliated Hospital, University of South China, Hengyang, Hunan, P. R. China
| | - Li Wang
- Department of Anthropotomy, Medical College, University of South China, Hengyang, Hunan, P.R. China
| | - Ming Xie
- Department of Anesthesiology, the First Affiliated Hospital, University of South China, Hengyang, Hunan, P. R. China
- Department of Neurology, the First Affiliated Hospital, University of South China, Hengyang, Hunan, P. R. China
- * E-mail: (X-QT); (MX)
| | - Chun-Yan Wang
- Department of Pathophysiology, Medical College, University of South China, Hengyang, Hunan, P.R. China
| | - Xiao-Qing Tang
- Department of Anesthesiology, the First Affiliated Hospital, University of South China, Hengyang, Hunan, P. R. China
- Institute of Neuroscience, Medical College, University of South China, Hengyang, Hunan, P. R. China
- * E-mail: (X-QT); (MX)
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Wang F, Li C, Liu W, Jin Y. Potential mechanisms of neurobehavioral disturbances in mice caused by sub-chronic exposure to low-dose VOCs. Inhal Toxicol 2014; 26:250-8. [DOI: 10.3109/08958378.2014.882447] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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13
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Children living near chipboard and wood industries are at an increased risk of hospitalization for respiratory diseases: A prospective study. Int J Hyg Environ Health 2014; 217:95-101. [DOI: 10.1016/j.ijheh.2013.03.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 03/14/2013] [Accepted: 03/26/2013] [Indexed: 01/21/2023]
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Boyer IJ, Heldreth B, Bergfeld WF, Belsito DV, Hill RA, Klaassen CD, Liebler DC, Marks JG, Shank RC, Slaga TJ, Snyder PW, Andersen FA. Amended Safety Assessment of Formaldehyde and Methylene Glycol as Used in Cosmetics. Int J Toxicol 2013; 32:5S-32S. [DOI: 10.1177/1091581813511831] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Formaldehyde and methylene glycol may be used safely in cosmetics if established limits are not exceeded and are safe for use in nail hardeners in the present practices of use and concentration, which include instructions to avoid skin contact. In hair-smoothing products, however, in the present practices of use and concentration, formaldehyde and methylene glycol are unsafe. Methylene glycol is continuously converted to formaldehyde, and vice versa, even at equilibrium, which can be easily shifted by heating, drying, and other conditions to increase the amount of formaldehyde. This rapid, reversible formaldehyde/methylene glycol equilibrium is distinguished from the slow, irreversible release of formaldehyde resulting from the so-called formaldehyde releaser preservatives, which are not addressed in this safety assessment (formaldehyde releasers may continue to be safely used in cosmetics at the levels established in their individual Cosmetic Ingredient Review safety assessments).
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Affiliation(s)
- Ivan J. Boyer
- Cosmetic Ingredient Review Toxicologist, Washington, DC, USA
| | - Bart Heldreth
- Cosmetic Ingredient Review Chemist, Washington, DC, USA
| | | | | | - Ronald A. Hill
- Cosmetic Ingredient Review Expert Panel Member, Washington, DC, USA
| | | | | | - James G. Marks
- Cosmetic Ingredient Review Expert Panel Member, Washington, DC, USA
| | - Ronald C. Shank
- Cosmetic Ingredient Review Expert Panel Member, Washington, DC, USA
| | - Thomas J. Slaga
- Cosmetic Ingredient Review Expert Panel Member, Washington, DC, USA
| | - Paul W. Snyder
- Cosmetic Ingredient Review Expert Panel Member, Washington, DC, USA
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Porzionato A, Macchi V, Zaramella P, Sarasin G, Grisafi D, Dedja A, Chiandetti L, De Caro R. Effects of postnatal hyperoxia exposure on the rat dentate gyrus and subventricular zone. Brain Struct Funct 2013; 220:229-47. [PMID: 24135771 DOI: 10.1007/s00429-013-0650-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2013] [Accepted: 10/04/2013] [Indexed: 12/27/2022]
Abstract
Premature newborns may be exposed to hyperoxia in the first postnatal period, but clinical and experimental works have raised the question of oxygen toxicity for the developing brain. However, specific analysis of hyperoxia exposure on neurogenesis is still lacking. Thus, the aim of the present study was to evaluate possible changes in the morphometric parameters of the main neurogenic sites in newborn rats exposed to 60 or 95 % oxygen for the first 14 postnatal days. The optical disector, a morphometric method based upon unbiased sampling principles of stereology, was applied to analyse cell densities, total volumes, and total cell numbers of the dentate gyrus (DG) and subventricular zone (SVZ). Apoptosis and proliferation were also studied by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling method and anti-ki67 immunohistochemistry, respectively. Severe hyperoxia increased the percentage of apoptotic cells in the DG. Moderate and severe hyperoxia induced a proliferative response both in the DG and SVZ, but the two neurogenic sites showed different changes in their morphometric parameters. The DG of both the hyperoxic groups showed lower volume and total cell number than that of the normoxic one. Conversely, the SVZ of newborn rats exposed to 95 % hyperoxia showed statistically significant higher volume and total cell number than SVZ of rats raised in normoxia. Our findings indicate that hyperoxia exposure in the first postnatal period affects both the neurogenic areas, although in different ways, i.e. reduction of DG and expansion of SVZ.
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Affiliation(s)
- Andrea Porzionato
- Section of Anatomy, Department of Molecular Medicine, University of Padova, Via A Gabelli 65, 35127, Padua, Italy
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Tulpule K, Dringen R. Formaldehyde in brain: an overlooked player in neurodegeneration? J Neurochem 2013; 127:7-21. [PMID: 23800365 DOI: 10.1111/jnc.12356] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 06/12/2013] [Accepted: 06/21/2013] [Indexed: 02/06/2023]
Abstract
Formaldehyde is an environmental pollutant that is also generated in substantial amounts in the human body during normal metabolism. This aldehyde is a well-established neurotoxin that affects memory, learning, and behavior. In addition, in several pathological conditions, including Alzheimer's disease, an increase in the expression of formaldehyde-generating enzymes and elevated levels of formaldehyde in brain have been reported. This article gives an overview on the current knowledge on the generation and metabolism of formaldehyde in brain cells as well as on formaldehyde-induced alterations in metabolic processes. Brain cells have the potential to generate and to dispose formaldehyde. In culture, both astrocytes and neurons efficiently oxidize formaldehyde to formate which can be exported or further oxidized. Although moderate concentrations of formaldehyde are not acutely toxic for brain cells, exposure to formaldehyde severely affects their metabolism as demonstrated by the formaldehyde-induced acceleration of glycolytic flux and by the rapid multidrug resistance protein 1-mediated export of glutathione from both astrocytes and neurons. These formaldehyde-induced alterations in the metabolism of brain cells may contribute to the impaired cognitive performance observed after formaldehyde exposure and to the neurodegeneration in diseases that are associated with increased formaldehyde levels in brain.
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Affiliation(s)
- Ketki Tulpule
- Indian Institute of Science Education and Research, Pashan, Pune, India
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Costa LM, Pereira JE, Filipe VM, Magalhães LG, Couto PA, Gonzalo-Orden JM, Raimondo S, Geuna S, Maurício AC, Nikulina E, Filbin MT, Varejão AS. Rolipram promotes functional recovery after contusive thoracic spinal cord injury in rats. Behav Brain Res 2013; 243:66-73. [DOI: 10.1016/j.bbr.2012.12.056] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2012] [Revised: 12/24/2012] [Accepted: 12/29/2012] [Indexed: 01/28/2023]
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Kalkan Y, Unal B, Keles ON, Kara A. Numerical analysis of age and gender-dependent neuronal cells in postnatal development of rat hippocampus. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/j.npbr.2012.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Tang XQ, Fang HR, Zhou CF, Zhuang YY, Zhang P, Gu HF, Hu B. A novel mechanism of formaldehyde neurotoxicity: inhibition of hydrogen sulfide generation by promoting overproduction of nitric oxide. PLoS One 2013; 8:e54829. [PMID: 23359814 PMCID: PMC3554621 DOI: 10.1371/journal.pone.0054829] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 12/17/2012] [Indexed: 12/29/2022] Open
Abstract
Background Formaldehyde (FA) induces neurotoxicity by overproduction of intracellular reactive oxygen species (ROS). Increasing studies have shown that hydrogen sulfide (H2S), an endogenous gastransmitter, protects nerve cells against oxidative stress by its antioxidant effect. It has been shown that overproduction of nitric oxide (NO) inhibits the activity of cystathionine-beta-synthase (CBS), the predominant H2S-generating enzyme in the central nervous system. Objective We hypothesize that FA-caused neurotoxicity involves the deficiency of this endogenous protective antioxidant gas, which results from excessive generation of NO. The aim of this study is to evaluate whether FA disturbs H2S synthesis in PC12 cells, and whether this disturbance is associated with overproduction of NO. Principal Findings We showed that exposure of PC12 cells to FA causes reduction of viability, inhibition of CBS expression, decrease of endogenous H2S production, and NO production. CBS silencing deteriorates FA-induced decreases in endogenous H2S generation, neurotoxicity, and intracellular ROS accumulation in PC12 cells; while ADMA, a specific inhibitor of NOS significantly attenuates FA-induced decreases in endogenous H2S generation, neurotoxicity, and intracellular ROS accumulation in PC12 cells. Conclusion/Significance Our data indicate that FA induces neurotoxicity by inhibiting the generation of H2S through excess of NO and suggest that strategies to manipulate endogenous H2S could open a suitable novel therapeutic avenue for FA-induced neurotoxicity.
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Affiliation(s)
- Xiao-Qing Tang
- Department of Physiology, Medical College, University of South China, Hengyang, Hunan, P. R. China
- * E-mail: (X-QT); (PZ)
| | - Heng-Rong Fang
- Department of Physiology, Medical College, University of South China, Hengyang, Hunan, P. R. China
- Department of Pharmacy, Hengyang Central Hospital, Hengyang, Hunan, P. R. China
| | - Cheng-Fang Zhou
- Department of Physiology, Medical College, University of South China, Hengyang, Hunan, P. R. China
| | - Yuan-Yuan Zhuang
- Department of Physiology, Medical College, University of South China, Hengyang, Hunan, P. R. China
| | - Ping Zhang
- Department of Neurology, Nanhua Affiliated Hospital, University of South China, Hengyang, Hunan, P. R. China
- * E-mail: (X-QT); (PZ)
| | - Hong-Feng Gu
- Department of Physiology, Medical College, University of South China, Hengyang, Hunan, P. R. China
| | - Bi Hu
- Department of Physiology, Medical College, University of South China, Hengyang, Hunan, P. R. China
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Monfared AL. Histomorphological and ultrastructural changes of the placenta in mice exposed to formaldehyde. Toxicol Ind Health 2012; 30:174-81. [PMID: 22778113 DOI: 10.1177/0748233712452603] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Formaldehyde (FA) is widely used in industrial and medical settings. It has long been suspected of causing adverse reproductive and developmental effects. However, the effects of exposure to FA on the reproduction are still a matter of scientific controversy. In this study, we evaluate the hypothesis that adverse developmental outcomes of the exposure to FA might be due to its effects on the placental structure. So, histological changes of the placenta in the mice exposed to FA gas were assessed at light and electron microscopy levels. A total of 40 pregnant Balb/C mice were randomly allotted to four groups in which the animals were exposed to FA at the doses of 0 (control), 7, 14 and 28 ppm, respectively, by inhalation, consecutively, for 8 h/d during the organogenesis period. On day 17 of gestation, the animals were killed and the histological specimens of the placentas were taken for light and electron microscopy studies. Also, morphological parameters of the placentas were measured manually. The results showed that the effects of FA on the placenta are not dose dependent. In the FA-exposed mice, an increase in the number and size of trophoblastic giant cells and an enlargement of spongiotrophoblastic cells in the basal zone of placenta were seen. Also, a significant increase in placental weight as well as the ratio of placental to fetal weight but a decrease in the fetal weight were found in the treated groups when compared with those in the control mice (p < 0.05). Moreover, ultrastructural results demonstrated that the diameter of labyrinth interhemal membrane as well as the thickness of trophoblastic basement membranes were significantly increased in the FA-exposed mice. In addition, in the FA-treated animals, a severe accumulation of cytoplasmic droplets in the II and III trophoblastic layers of the placenta were seen. In conclusion, this study may suggest that the exposure to FA during the organogenesis period at doses of 7-28 ppm induces toxic changes in the placental structure. These changes disrupt placental functions and leads to a decrease in the fetal weight.
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Affiliation(s)
- Ali Louei Monfared
- Division of Anatomy and Histology, Department of Basic Sciences, Faculty of Para-Veterinary Medicine, University of Ilam, Ilam, Iran
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Hydrogen sulfide prevents formaldehyde-induced neurotoxicity to PC12 cells by attenuation of mitochondrial dysfunction and pro-apoptotic potential. Neurochem Int 2012; 61:16-24. [PMID: 22542418 DOI: 10.1016/j.neuint.2012.04.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2011] [Revised: 04/08/2012] [Accepted: 04/11/2012] [Indexed: 11/23/2022]
Abstract
Hydrogen sulfide (H(2)S) has been shown to act as a neuroprotectant and antioxidant. Numerous studies have demonstrated that exposure to formaldehyde (FA) causes neuronal damage and that oxidative stress is one of the most critical effects of FA exposure. Accumulation of FA is involved in the pathogenesis of Alzheimer's disease (AD). The aim of present study is to explore the inhibitory effects of H(2)S on FA-induced cytotoxicity and apoptosis and the molecular mechanisms underlying in PC12 cells. We show that sodium hydrosulfide (NaHS), a H(2)S donor, protects PC12 cells against FA-mediated cytotoxicity and apoptosis and that NaHS preserves the function of mitochondria by preventing FA-induced loss of mitochondrial membrane potential and release of cytochrome c in PC12 cells. Furthermore, NaHS blocks FA-exerted accumulation of intracellular reactive oxygen species (ROS), down-regulation of Bcl-2 expression, and up-regulation of Bax expression. These results indicate that H(2)S protects neuronal cells against neurotoxicity of FA by preserving mitochondrial function through attenuation of ROS accumulation, up-regulation of Bcl-2 level, and down-regulation of Bax expression. Our study suggests a promising future of H(2)S-based preventions and therapies for neuronal damage after FA exposure.
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Tang XQ, Ren YK, Chen RQ, Zhuang YY, Fang HR, Xu JH, Wang CY, Hu B. Formaldehyde induces neurotoxicity to PC12 cells involving inhibition of paraoxonase-1 expression and activity. Clin Exp Pharmacol Physiol 2011; 38:208-14. [PMID: 21261675 DOI: 10.1111/j.1440-1681.2011.05485.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
1. Formaldehyde (FA) has been found to cause toxicity to neurons. However, its neurotoxic mechanisms have not yet been clarified. Increasing evidence has shown that oxidative damage is one of the most critical effects of formaldehyde exposure. Paraoxonase-1 (PON-1) is a pivotal endogenous anti-oxidant. Thus, we hypothesized that FA-mediated downregulation of PON1 is associated with its neurotoxicity. 2. In the present work, we used PC12 cells to study the neurotoxicity of FA and explore whether PON-1 is implicated in FA-induced neurotoxicity. 3. We found that FA has potent cytotoxic and apoptotic effects on PC12 cells. FA induces an accumulation of intracellular reactive oxygen species along with downregulation of Bcl-2 expression, as well as increased cytochrome c release. FA significantly suppressed the expression and activity of PON-1 in PC12 cells. Furthermore, H(2)S, an endogenous anti-oxidant gas, antagonizes FA-induced cytotoxicity as well as 2-hydroxyquinoline, a specific inhibitor of PON-1, which also induces cytotoxicity to PC12 cells. 4. The results of the present study provide, for the first time, evidence that the inhibitory effect on PON-1 expression and activity is involved in the neurotoxicity of FA, and suggest a promising role of PON-1 as a novel therapeutic strategy for FA-mediated toxicity.
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Affiliation(s)
- Xiao-Qing Tang
- Department of Physiology, Medical College, University of South China, Hengyang, Hunan, China.
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TONG ZQ, HAN CS, MIAO JY, LU J, HE RQ. Excess Endogenous Formaldehyde Induces Memory Decline*. PROG BIOCHEM BIOPHYS 2011. [DOI: 10.3724/sp.j.1206.2011.00241] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Songur A, Ozen OA, Sarsilmaz M. The toxic effects of formaldehyde on the nervous system. REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2010; 203:105-118. [PMID: 19957118 DOI: 10.1007/978-1-4419-1352-4_3] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Formaldehyde (FA) is found in the polluted atmosphere of cities, domestic air (e.g., paint, insulating materials, chipboard and plywood, fabrics, furniture, paper), and cigarette smoke, etc.; therefore, everyone and particularly susceptible children may be exposed to FA. FA is also widely used in industrial and medical settings and as a sterilizing agent, disinfectant, and preservative. Therefore, employees may be highly exposed to it in there settings. Of particular concern to the authors are anatomists and medical students, who can be highly exposed to formaldehyde vapor during dissection sessions. Formaldehyde is toxic over a range of doses; chances of exposure and subsequent harmful effects are increased as (room) temperature increases, because of FA's volatility. Many studies have been conducted to evaluate the effects of FA during systemic and respiratory exposures in rats. This review compiles that literature and emphasizes the neurotoxic effects of FA on neuronal morphology, behavior, and biochemical parameters. The review includes the results of some of the authors' work related to FA neurotoxicity, and such neurotoxic effects from FA exposure were experimentally demonstrated. Moreover, the effectiveness of some antioxidants such as melatonin, fish omega-3, and CAPE was observed in the treatment of the harmful effects of FA. Despite the harmful effects from FA exposure, it is commonly used in Turkey and elsewhere in dissection laboratories. Consequently, all anatomists must know and understand the effects of this toxic agent on organisms and the environment, and take precautions to avoid unnecessary exposure. The reviewed studies have indicated that FA has neurotoxic characteristics and systemic toxic effects. It is hypothesized that inhalation of FA, during the early postnatal period, is linked to some neurological diseases that occur in adults. Although complete prevention is impossible for laboratory workers and members of industries utilizing FA, certain precautions can be taken to decrease and/or prevent the toxic effects of FA.
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Affiliation(s)
- Ahmet Songur
- Department of Anatomy, School of Medicine, University of Kocatepe, Afyonkarahisar, Turkey.
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Methylprednisolone fails to improve functional and histological outcome following spinal cord injury in rats. Exp Neurol 2009; 220:71-81. [DOI: 10.1016/j.expneurol.2009.07.030] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 07/27/2009] [Accepted: 07/28/2009] [Indexed: 11/22/2022]
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Weisskopf MG, Morozova N, O'Reilly EJ, McCullough ML, Calle EE, Thun MJ, Ascherio A. Prospective study of chemical exposures and amyotrophic lateral sclerosis. J Neurol Neurosurg Psychiatry 2009; 80:558-61. [PMID: 19372290 PMCID: PMC2765376 DOI: 10.1136/jnnp.2008.156976] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Although environmental toxins, including pesticides, are suspected of contributing to the risk of amyotrophic lateral sclerosis (ALS), no data exist from large prospective investigations. This study assessed the association between exposure to chemicals and risk of ALS in a prospective cohort study. METHODS The relation between self-report of regular exposure to 11 different chemical classes or x rays and ALS mortality among over 1 million participants in the American Cancer Society's Cancer Prevention Study II was prospectively assessed. Follow-up from 1989 through 2004 identified 617 deaths from ALS among men and 539 among women. Adjusted rate ratios (RR) were calculated using Cox proportional hazards. RESULTS The RR for ALS mortality among individuals exposed to pesticides/herbicides compared with that among unexposed individuals was 1.07 (95% CI 0.79 to 1.44), but somewhat higher after excluding those with missing duration of pesticides exposure (RR 1.44; 95% CI 0.89 to 2.31; p = 0.14). A non-significant increase in ALS mortality was found among individuals who reported exposure to formaldehyde (RR 1.34; 95% CI 0.93 to 1.92). Excluding those with a missing duration of formaldehyde exposure, the RR was 2.47 (95% CI 1.58 to 3.86), and there was a strongly significant dose-response relation with increasing years of exposure (p trend = 0.0004). CONCLUSIONS There was little evidence for any association between pesticides/herbicide exposure and ALS. In contrast, evidence was found, suggesting an increased risk of ALS with formaldehyde exposure. Because of the longitudinal design, this result is unlikely to be due to bias, but it should nevertheless be interpreted cautiously and needs to be verified independently.
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Affiliation(s)
- M G Weisskopf
- Harvard School of Public Health, Department of Environmental Health, Boston, MA 02215, USA.
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Effect of gestational ethanol exposure on parvalbumin and calretinin expressing hippocampal neurons in a chick model of fetal alcohol syndrome. Alcohol 2009; 43:147-61. [PMID: 19251116 DOI: 10.1016/j.alcohol.2008.12.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Revised: 10/29/2008] [Accepted: 12/09/2008] [Indexed: 01/12/2023]
Abstract
Fetal alcohol syndrome (FAS), a condition occurring in some children of mothers who have consumed alcohol during pregnancy, is characterized by physical deformities and learning and memory deficits. The chick hippocampus, whose functions are controlled by interneurons expressing calcium-binding proteins parvalbumin (PV) and calretinin (CR), is involved in learning and memory mechanisms. Effects on growth and development and hippocampal morphology were studied in chick embryos exposed to 5% and 10% ethanol volume/volume (vol/vol) for 2 or 8 days of gestation. There was a significant dose-dependent reduction (P<.05) in body weight and mean number per section of PV and CR expressing hippocampal neurons in ethanol-exposed chicks, without alterations in neuronal nuclear size or hippocampal volume, compared appropriate controls. Moreover, when chicks exposed to 5% ethanol for 2 and 8 days of gestation were compared, no significant differences were found in body parameters or neuronal counts. Similarly, exposure to 10% ethanol did not induce any significant changes in chicks exposed for 2 or 8 gestational days. Thus, these results suggest that gestational ethanol exposure induces a reduction in the mean number per section of PV and CR expressing hippocampal neurons, and could be a possible mechanism responsible for learning and memory disorders in FAS.
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Songur A, Sarsilmaz M, Ozen O, Sahin S, Koken R, Zararsiz I, Ilhan N. The Effects of Inhaled Formaldehyde on Oxidant and Antioxidant Systems of Rat Cerebellum During the Postnatal Development Process. Toxicol Mech Methods 2008; 18:569-74. [DOI: 10.1080/15376510701555288] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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29
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Canan S, Aktaş A, Ulkay MB, Colakoglu S, Ragbetli MC, Ayyildiz M, Geuna S, Kaplan S. Prenatal exposure to a non‐steroidal anti‐inflammatory drug or saline solution impairs sciatic nerve morphology: a stereological and histological study. Int J Dev Neurosci 2008; 26:733-8. [DOI: 10.1016/j.ijdevneu.2008.07.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Revised: 06/27/2008] [Accepted: 07/06/2008] [Indexed: 11/24/2022] Open
Affiliation(s)
- Sinan Canan
- Department of PhysiologyBaskent University School of MedicineTR‐06530AnkaraTurkey
| | - Abit Aktaş
- Department of Histology and EmbryologyIstanbul University School of Veterinary MedicineTR‐34320IstanbulTurkey
| | - M. Basak Ulkay
- Department of Histology and EmbryologyIstanbul University School of Veterinary MedicineTR‐34320IstanbulTurkey
| | - Serdar Colakoglu
- Department of AnatomyDuzce University School of MedicineDuzceTurkey
| | - Murat Cetin Ragbetli
- Department of Histology and EmbryologyYüzüncü Yıl University School of MedicineVanTurkey
| | - Mustafa Ayyildiz
- Department of PhysiologyOndokuz Mayis University School of MedicineSamsunTurkey
| | - Stefano Geuna
- Dipartimento Di Scienze Cliniche E BiologicheUniversity Torino Ospedale San LuigiRegione Gonzole10‐10043OrbassanoTorinoItaly
| | - Suleyman Kaplan
- Department of Histology and EmbryologyOndokuz Mayis University School of MedicineTR‐55139SamsunTurkey
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Sarsilmaz M, Kaplan S, Songur A, Colakoglu S, Aslan H, Tunc AT, Ozen OA, Turgut M, Baş O. Effects of postnatal formaldehyde exposure on pyramidal cell number, volume of cell layer in hippocampus and hemisphere in the rat: a stereological study. Brain Res 2007; 1145:157-67. [PMID: 17346681 DOI: 10.1016/j.brainres.2007.01.139] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2007] [Revised: 01/25/2007] [Accepted: 01/25/2007] [Indexed: 10/23/2022]
Abstract
The purpose of the present study was to determine whether exposure of neonatal rats to formaldehyde (FA) had either early or delayed effects on the numbers of pyramidal cells in the cornu ammonis (CA) of the hippocampus. Neonatal Wistar rats were exposed to 0 ppm (control group), 6 ppm and 12 ppm (high concentration group) of FA concentrations throughout the 30-day period following the birth by placing them for 6 h/day in a glass chamber containing FA vapor. Then, some of the animals from each FA-treated group were anesthetized and decapitated at the day 30, and the remaining ones were killed at the day 90. The brains were removed immediately and fixed in 10% neutral-buffered FA solution. The Cavalieri principle was used to determine the volumes of the CA and the entire cerebral hemisphere. The optical fractionator counting method was used to estimate the total number of pyramidal cells in the CA. The appearance of pyramidal cells was normal under light microscopy at both postnatal day (PND) 30 and PND 90 in all groups. There were concentration-related volume changes of CA at PND 30 and PND 90; low concentration of FA significantly increased, whereas high concentration decreased the volume of CA in comparison of the control at PND 30. Importantly, high concentration of FA at PND 90 increased the volume of CA in comparison of the low concentration but not with the control. Furthermore, low and high concentrations of FA decreased the volume of hemisphere at PND 30, whereas a reverse effect of these concentrations was observed at the hemisphere of PND 90 in comparison of the control. In both CA and cerebral hemisphere, an age-related volume decrease in both control and low/high concentration groups were found. On the other hand, there were significant age-related reductions in the total number of pyramidal cells at 90 days of age irrespective of the groups examined. Rats treated with high concentration FA were seen to have significantly fewer pyramidal cell neurons than either the animals treated with low concentration FA or control groups (p<0.01). These observations indicate that pyramidal cells in the hippocampus may be vulnerable to FA exposure during the early period of life.
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Affiliation(s)
- Mustafa Sarsilmaz
- Department of Anatomy, Firat University School of Medicine, Elazig, Turkey
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Amyloid-like aggregates of neuronal tau induced by formaldehyde promote apoptosis of neuronal cells. BMC Neurosci 2007; 8:9. [PMID: 17241479 PMCID: PMC1790706 DOI: 10.1186/1471-2202-8-9] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2006] [Accepted: 01/23/2007] [Indexed: 12/23/2022] Open
Abstract
Background The microtubule associated protein tau is the principle component of neurofibrillar tangles, which are a characteristic marker in the pathology of Alzheimer's disease; similar lesions are also observed after chronic alcohol abuse. Formaldehyde is a common environmental contaminant and also a metabolite of methanol. Although many studies have been done on methanol and formaldehyde intoxication, none of these address the contribution of protein misfolding to the pathological mechanism, in particular the effect of formaldehyde on protein conformation and polymerization. Results We found that unlike the typical globular protein BSA, the natively-unfolded structure of human neuronal tau was induced to misfold and aggregate in the presence of ~0.01% formaldehyde, leading to formation of amyloid-like deposits that appeared as densely staining granules by electron microscopy and atomic force microscopy, and bound the amyloid-specific dyes thioflavin T and Congo Red. The amyloid-like aggregates of tau were found to induce apoptosis in the neurotypic cell line SH-SY5Y and in rat hippocampal cells, as observed by Hoechst 33258 staining, assay of caspase-3 activity, and flow cytometry using Annexin V and Propidium Iodide staining. Further experiments showed that Congo Red specifically attenuated the caspase-3 activity induced by amyloid-like deposits of tau. Conclusion The results suggest that low concentrations of formaldehyde can induce human tau protein to form neurotoxic aggregates, which could play a role in the induction of tauopathies.
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Gokcimen A, Rağbetli MC, Baş O, Tunc AT, Aslan H, Yazici AC, Kaplan S. Effect of prenatal exposure to an anti-inflammatory drug on neuron number in cornu ammonis and dentate gyrus of the rat hippocampus: A stereological study. Brain Res 2007; 1127:185-92. [PMID: 17123485 DOI: 10.1016/j.brainres.2006.10.026] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2006] [Revised: 10/14/2006] [Accepted: 10/17/2006] [Indexed: 11/19/2022]
Abstract
Prenatal exposed to an anti-inflammatory drug is a major problem for the developing central nervous system. It is not well known the effect of prenatal exposed to a non-steroidal anti-inflammatory drug on the hippocampus. Total neuron number in one side of the cornu ammonis (CA) and gyrus dentatus (GD) of the hippocampal formation in control and drug-treated (diclofenac sodium, DS) groups of male rats was estimated using the optical fractionator technique. Each main group has also two subgroups that are 4 weeks old (4W-old) and 20 weeks old (20W-old). In CA, no significant difference between 4W-old DS-treated and their control was found, but a significant difference was observed between 20W-old DS-treated and their controls. A decreasing of neuron number was 12% for 20W-old DS-treated group. In GD, a decreasing of the granule cell number in 4W-old of DS-treated group was seen but an increasing of granule cell number was found in the 20W-old drug-treated rats in comparison to its control group, 7% and 9%, respectively. Although an increasing of neuron number in CA at the control group was seen with age, from 4th week to 20th week (10%), age-dependent substantial granule cell decline (17%) was observed in GD. No age effect on the total cell numbers of CA and GD of the drug-treated groups was seen in comparison to 4W-old week and 20W-old. A pronounced neuron loss observed in the drug-treated group may be attributed to the neurotoxicity of diclofenac sodium (DS) on the developing hippocampal formation. Age-dependent neuron increase in the CA of 20W-old and neuron decline in GD of 20W-old control groups may be a result of a dual effect of saline injection during the fetal life, since these animals were exposed to a stress of 15-day-period of saline injection, prenatal stress. The reason of no age effect on CA and GD cell number in the drug-treated groups may be attributed to the depletion of the progenitor cells due to neurotoxicity of DS in the fetal life of these animals.
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Affiliation(s)
- Alpaslan Gokcimen
- Department of Histology and Embryology, Süleyman Demirel University School of Medicine, Isparta, Turkey
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Turgut M, Turkkani Tunc A, Aslan H, Yazici AC, Kaplan S. Effect of pinealectomy on the morphology of the chick cervical spinal cord: a stereological and histopathological study. Brain Res 2006; 1129:166-73. [PMID: 17157276 DOI: 10.1016/j.brainres.2006.10.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2006] [Revised: 10/11/2006] [Accepted: 10/14/2006] [Indexed: 11/28/2022]
Abstract
Melatonin has some effects upon morphological features of various structures in small animals and human being. In this study, the changes induced by pinealectomy procedure on morphological features of developing cervical spinal cord and their neurons in the gray matter (GM) and white matter (WM) of cervical spinal cord in the chicken were investigated. A total of 15 Hybro Broiler newly hatched chicks were randomly divided into three equal groups: unoperated control group (n=5), sham-operated group (n=5) and pinealectomy group (n=5). Pinealectomy procedure and sham operation were done in 3-day-old chicks and all animals were sacrificed at the 8th week and the 6th cervical (C6) spinal cord segment was dissected out for histopathological evaluation and subsequent stereological analysis. The volume of spinal cord segment did not show a significant difference between unoperated and sham-operated controls, but the pinealectomy group has a declined volume value compared with those of the control and sham operated groups (P<0.01). By contrast, there was no statistically significant difference between unoperated and sham-operated controls and the pinealectomy group with regard to volume fraction of the GM and WM of the cervical spinal cord. Finally, it was observed that pinealectomy procedure significantly reduces neuron number in the GM and the volume of WM of the C6 segment of cervical spinal cord in the chicken (P<0.001). The present study is the first study at all to evaluate the effects of pinealectomy on quantitative feature of the spinal cord in the chicken. Based on our findings, we suggest that pineal gland/melatonin might play an important role in morphological features of the developing spinal cord in the chicken.
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Affiliation(s)
- Mehmet Turgut
- Department of Neurosurgery, Adnan Menderes University School of Medicine, Aydin, Turkey
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