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Paciello F, Pisani A, Rolesi R, Montuoro R, Mohamed-Hizam V, Boni G, Ripoli C, Galli J, Sisto R, Fetoni AR, Grassi C. Oxidative stress and inflammation cause auditory system damage via glial cell activation and dysregulated expression of gap junction proteins in an experimental model of styrene-induced oto/neurotoxicity. J Neuroinflammation 2024; 21:4. [PMID: 38178142 PMCID: PMC10765700 DOI: 10.1186/s12974-023-02996-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 12/13/2023] [Indexed: 01/06/2024] Open
Abstract
BACKGROUND Redox imbalance and inflammation have been proposed as the principal mechanisms of damage in the auditory system, resulting in functional alterations and hearing loss. Microglia and astrocytes play a crucial role in mediating oxidative/inflammatory injury in the central nervous system; however, the role of glial cells in the auditory damage is still elusive. OBJECTIVES Here we investigated glial-mediated responses to toxic injury in peripheral and central structures of the auditory pathway, i.e., the cochlea and the auditory cortex (ACx), in rats exposed to styrene, a volatile compound with well-known oto/neurotoxic properties. METHODS Male adult Wistar rats were treated with styrene (400 mg/kg daily for 3 weeks, 5/days a week). Electrophysiological, morphological, immunofluorescence and molecular analyses were performed in both the cochlea and the ACx to evaluate the mechanisms underlying styrene-induced oto/neurotoxicity in the auditory system. RESULTS We showed that the oto/neurotoxic insult induced by styrene increases oxidative stress in both cochlea and ACx. This was associated with macrophages and glial cell activation, increased expression of inflammatory markers (i.e., pro-inflammatory cytokines and chemokine receptors) and alterations in connexin (Cxs) and pannexin (Panx) expression, likely responsible for dysregulation of the microglia/astrocyte network. Specifically, we found downregulation of Cx26 and Cx30 in the cochlea, and high level of Cx43 and Panx1 in the ACx. CONCLUSIONS Collectively, our results provide novel evidence on the role of immune and glial cell activation in the oxidative/inflammatory damage induced by styrene in the auditory system at both peripheral and central levels, also involving alterations of gap junction networks. Our data suggest that targeting glial cells and connexin/pannexin expression might be useful to attenuate oxidative/inflammatory damage in the auditory system.
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Affiliation(s)
- Fabiola Paciello
- Department of Neuroscience, Università Cattolica del Sacro Cuore, 00168, Rome, Italy
- Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168, Rome, Italy
| | - Anna Pisani
- Department of Head and Neck Surgery, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Rolando Rolesi
- Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168, Rome, Italy
- Department of Head and Neck Surgery, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Raffaele Montuoro
- Department of Head and Neck Surgery, Università Cattolica del Sacro Cuore, Rome, Italy
| | | | - Giammarco Boni
- Department of Neuroscience, Università Cattolica del Sacro Cuore, 00168, Rome, Italy
| | - Cristian Ripoli
- Department of Neuroscience, Università Cattolica del Sacro Cuore, 00168, Rome, Italy
- Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168, Rome, Italy
| | - Jacopo Galli
- Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168, Rome, Italy
- Department of Head and Neck Surgery, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Renata Sisto
- Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, Italian Workers' Compensation Authority (INAIL), Monte Porzio Catone, Rome, Italy
| | - Anna Rita Fetoni
- Department of Neuroscience, Unit of Audiology, Università Degli Studi di Napoli Federico II, Naples, Italy.
| | - Claudio Grassi
- Department of Neuroscience, Università Cattolica del Sacro Cuore, 00168, Rome, Italy
- Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168, Rome, Italy
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Chung JY, Park JE, Kim YJ, Lee SJ, Yu WJ, Kim JM. Styrene Cytotoxicity in Testicular Leydig Cells In Vitro. Dev Reprod 2022; 26:99-105. [PMID: 36285149 PMCID: PMC9578320 DOI: 10.12717/dr.2022.26.3.99] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 08/03/2022] [Accepted: 08/22/2022] [Indexed: 11/17/2022]
Abstract
Styrene is the precursor of polystyrene. Human exposure to styrene could occur in occupational and residential settings and via food intake. Styrene is metabolized to styrene-7,8-oxide by cytochrome P450 enzyme. In the present study, we investigated the cytotoxicity mediated by styrene and styrene-7,8-oxide in TM3 testicular Leydig cells in vitro. We first monitored the nuclear fragmentation in Leydig cells after exposure to styrene or styrene-7,8-oxide. Hoechst 33258 cell staining showed that styrene exposure in TM3 Leydig cells did not exhibit nuclear fragmentation at any concentration. In contrast, nuclear fragmentation was seen in styrene-7,8-oxide-exposed cells. These results indicate that cytotoxicity-mediated cell death in Leydig cells is more susceptible to styrene-7,8-oxide than to styrene. Following styrene treatment, procaspase-3 and XIAP protein levels did not show significant changes, and cleaved (active) forms of caspase-3 were not detected. Consistent with the western blot results, the active forms of caspase-3 and XIAP proteins were not prominently altered in the cytoplasm of cells treated with styrene. In contrast to styrene, styrene-7,8-oxide induced cell death in an apoptotic fashion, as seen in caspase-3 activation and increased the expression of XIAP proteins. Taken together, the results obtained in this study demonstrate a fundamental idea that Leydig cells are capable of protecting themselves from cytotoxicity-mediated apoptosis as a result of styrene exposure in vitro. It remains unclear whether the steroid-producing function, i.e., steroidogenesis, of Leydig cells is also unaffected by exposure to styrene. Therefore, further studies are needed to elucidate the endocrine disrupting potential of styrene in Leydig cells.
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Affiliation(s)
- Jin-Yong Chung
- Department of Anatomy and Cell Biology,
College of Medicine, Dong-A University, Busan
49201, Korea
| | - Ji-Eun Park
- Department of Anatomy and Cell Biology,
College of Medicine, Dong-A University, Busan
49201, Korea
| | - Yoon-Jae Kim
- Department of Anatomy and Cell Biology,
College of Medicine, Dong-A University, Busan
49201, Korea
| | - Seung-Jin Lee
- Developmental and Reproductive Toxicology
Research Group, Korea Institute of Toxicology,
Daejeon 34114, Korea
| | - Wook-Joon Yu
- Developmental and Reproductive Toxicology
Research Group, Korea Institute of Toxicology,
Daejeon 34114, Korea
| | - Jong-Min Kim
- Department of Anatomy and Cell Biology,
College of Medicine, Dong-A University, Busan
49201, Korea,Corresponding author Jong-Min
Kim, Department of Anatomy and Cell Biology, College of Medicine, Dong-A
University, Busan 49201, Korea. Tel: +82-51-240-2792, E-mail:
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3
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Sarma A, Das MK. Improving the sustainable performance of Biopolymers using nanotechnology. POLYM-PLAST TECH MAT 2021. [DOI: 10.1080/25740881.2021.1937645] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Anupam Sarma
- Department of Pharmaceutics, Girijananda Chowdhury Institute of Pharmaceutical Science, Guwahati, Assam, India
| | - Malay K Das
- Drug Delivery Research Laboratory, Department of Pharmaceutical Sciences, Dibrugarh University, Dibrugarh, Assam, India
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4
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Fetoni AR, Paciello F, Rolesi R, Pisani A, Moleti A, Sisto R, Troiani D, Paludetti G, Grassi C. Styrene targets sensory and neural cochlear function through the crossroad between oxidative stress and inflammation. Free Radic Biol Med 2021; 163:31-42. [PMID: 33307165 DOI: 10.1016/j.freeradbiomed.2020.12.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 11/30/2020] [Accepted: 12/02/2020] [Indexed: 01/12/2023]
Abstract
BACKGROUND Although styrene is an established ototoxic agent at occupational exposure levels, the mechanisms of styrene toxicity in the auditory system are still unclear. OBJECTIVES The aim of this study was to identify the consequences of styrene chronic exposure in cochlear structures, looking for the mechanisms of ototoxicity of this organic compound and focusing on cell targets and oxidative stress/inflammatory processes. METHODS Male adult Wistar rats were exposed to styrene (400 mg/kg by gavage for 5 days/week, 3 consecutive weeks). Hearing loss was evaluated by measuring auditory brainstem responses (ABR), morphological analysis were performed to evaluate hair cell and spiral ganglion neuron survival, as well as synaptic damage. Analysis of apoptotic (p53) and inflammatory (NF-κB, TNF-α, IL-1β and IL-10) mediators were performed by immunofluorescence analysis and western blot. RESULTS Styrene ototoxic effects induced a hearing loss of about 35-40 dB. Immunofluorescence and western blotting analyses demonstrated that styrene administration induced redox imbalance and activated inflammatory processes, targeting sensory hair cell and neural dysfunction by a cross-talk between oxidative and inflammatory mediators. DISCUSSION Major findings connect styrene ototoxicity to an interplay between redox imbalance and inflammation, leading to the intriguing assumption of a mixed sensory and neural styrene-induced ototoxicity. Thus, in a clinical perspective, data reported here have important implications for styrene risk assessment in humans.
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Affiliation(s)
- Anna Rita Fetoni
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma, Italy; Department of Head and Neck Surgery, Università Cattolica Del Sacro Cuore, Roma, Italy.
| | - Fabiola Paciello
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma, Italy; Department of Neuroscience, Università Cattolica Del Sacro Cuore, Roma, Italy
| | - Rolando Rolesi
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma, Italy; Department of Head and Neck Surgery, Università Cattolica Del Sacro Cuore, Roma, Italy
| | - Anna Pisani
- Department of Head and Neck Surgery, Università Cattolica Del Sacro Cuore, Roma, Italy
| | - Arturo Moleti
- Department of Physics, University of Roma Tor Vergata, Roma, Italy
| | - Renata Sisto
- Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, Italian Workers' Compensation Authority (INAIL), Monte Porzio Catone (RM), Italy
| | - Diana Troiani
- Department of Neuroscience, Università Cattolica Del Sacro Cuore, Roma, Italy
| | - Gaetano Paludetti
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma, Italy; Department of Head and Neck Surgery, Università Cattolica Del Sacro Cuore, Roma, Italy
| | - Claudio Grassi
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma, Italy; Department of Neuroscience, Università Cattolica Del Sacro Cuore, Roma, Italy
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Moujahed S, Ruiz A, Hallegue D, Sakly M. Quercetin alleviates styrene oxide-induced cytotoxicity in cortical neurons in vitro via modulation of oxidative stress and apoptosis. Drug Chem Toxicol 2020; 45:1634-1643. [PMID: 33297769 DOI: 10.1080/01480545.2020.1851706] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Styrene 7,8-oxide (SO) is the principal metabolite of styrene, an industrial neurotoxic compound which causes various neurodegenerative disorders. The present study aimed to explore the mechanisms of SO cytotoxicity (0.5 - 4 mM) in primary cortical neurons and to evaluate the neuroprotective potential of quercetin (QUER). Our results showed that exposure to SO decreased viability of cortical neurons in a concentration-dependent manner. In the presence of QUER, cell viability was increased significantly. The neuroprotective effects of QUER were associated with the reduction of intracellular Reactive Oxygen Species (ROS), the decrease in calcium overload and the restoration of mitochondrial membrane depolarization caused by SO. Additionally, to evaluate neuronal death mechanisms triggered by SO, cells were incubated with Ac-DEVD-CHO, Calpeptin and Necrostatin-1, pharmacological inhibitors of caspase-3, calpains and necroptosis respectively. The data showed that the three inhibitors reduced cell death induced by SO and suggested the implication of apoptotic, necrotic and necroptotic pathways. However, western blot analysis showed that QUER attenuated the activation of caspase-3 but did not prevent calpain activity. Taken together, these data indicated that the cytotoxicity of SO was mediated by oxidative stress and apoptosis, necrosis and necroptosis mechanisms, while the neuroprotection provided by QUER against SO depended mainly on its anti-apoptotic activity.
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Affiliation(s)
- Sabrine Moujahed
- Faculty of Sciences of Bizerte, Laboratory of Integrative Physiology, University of Carthage, Jarzouna, Tunisia
| | - Asier Ruiz
- Faculty of Medicine and Nursing, Department of Neurosciences, University of the Basque Country, Vizcaya, Spain
| | - Dorsaf Hallegue
- Faculty of Sciences of Bizerte, Laboratory of Integrative Physiology, University of Carthage, Jarzouna, Tunisia
| | - Mohsen Sakly
- Faculty of Sciences of Bizerte, Laboratory of Integrative Physiology, University of Carthage, Jarzouna, Tunisia
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6
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Salehpour S, Amani R, Nili-Ahmadabadi A. Volatile Organic Compounds as a Preventive Health Challenge in the Petrochemical Industries. Int J Prev Med 2019; 10:194. [PMID: 31772726 PMCID: PMC6868646 DOI: 10.4103/ijpvm.ijpvm_495_18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 04/18/2019] [Indexed: 11/04/2022] Open
Abstract
Background The aim of this study was to assess the effects of long-term exposure to VOCs on employees' clinical parameters in one of the main petroleum centers in Iran. Methods In this case-control study, 80 operational and administrative employees with 8-15 years of work experience were considered as the case and control groups. Liver function was evaluated by measuring serum alanine transaminase (ALT) activity and lipid profile was measured. Gas chromatography-mass spectrometry (GC-MS) was used to analyze the VOCs levels at the workplace. Results There were increased levels of serum ALT (P = 0.003), triglycerides (P = 0.015), total cholesterol (P = 0.003), and LDL-C (P = 0.010) among the operational staffs compared to the administrative staffs. Assessment of the relationship between worksite pollutants and ALT levels revealed that there were significant positive relationship between benzene (r = 0.45, P = 0.004) and styrene (r = 0.37, P = 0.034) with increased ALT concentrations. Conclusions VOC exposure could be contributed to reduced liver function and impaired lipid profile. Therefore, proper preventive strategies seem to be necessary for reducing hazardous exposure.
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Affiliation(s)
- Sara Salehpour
- Department of Toxicology, Faculty of Pharmacy, Islamic Azad University, Shahreza Branch, Shahreza, Iran
| | - Reza Amani
- Department of Clinical Nutrition, School of Nutrition and Food Science, Food Security Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Amir Nili-Ahmadabadi
- Department of Pharmacology and Toxicology, School of Pharmacy, Hamadan University of Medical Sciences, Hamadan, Iran
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7
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Niaz K, Hassan FI, Mabqool F, Khan F, Momtaz S, Baeeri M, Navaei-Nigjeh M, Rahimifard M, Abdollahi M. Effect of styrene exposure on plasma parameters, molecular mechanisms and gene expression in rat model islet cells. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2017; 54:62-73. [PMID: 28688303 DOI: 10.1016/j.etap.2017.06.020] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 06/20/2017] [Accepted: 06/21/2017] [Indexed: 06/07/2023]
Abstract
Styrene is an aromatic hydrocarbon compound present in the environment and have primary exposure through plastic industry. The current study was designed to evaluate styrene-induced toxicity parameters in rat plasma fasting blood glucose (FBG) level, oral glucose tolerance, insulin secretion, oxidative stress, and inflammatory cytokines in cellular and molecular levels. Styrene was dissolved in corn oil and administered at different doses (250, 500, 1000, 1500, 2000mg/kg/day and control) to each rat, for 42days. In treated groups, styrene significantly increased fasting blood glucose, plasma insulin (p<0.001) and glucose tolerance. Glucose tolerance, insulin resistance and hyperglycemia were found to be the main consequences correlating gene expression of islet cells. Styrene caused a significant enhancement of oxidative stress markers (p<0.001) and inflammatory cytokines in a dose and concentration-dependent manner in plasma (p<0.001). Moreover, the activities of caspase-3 and -9 of the islet cells were significantly up-regulated by this compound at 1500 and 2000mg/kg/day styrene administrated groups (p<0.001). The relative fold change of GLUD1 was downregulated (p<0.05) and upregulated at 1500 and 2000mg/kg, respectively (p<0.01). The relative fold changes of GLUT2 were down regulated at 250 and 1000mg/kg and up regulated in 500, 1500 and 2000mg/kg doses of styrene (p<0.01). The expression level of GCK indicated a significant upregulation at 250mg/kg and downregulation of relative fold changes in the remaining doses of styrene, except for no change at 2000mg/kg of styrene for GCK. Targeting genes (GLUD1, GLUT2 and GCK) of the pancreatic islet cells in styrene exposed groups, disrupted gluconeogenesis, glycogenolysis pathways and insulin secretory functions. The present study illustrated that fasting blood glucose, insulin pathway, oxidative balance, inflammatory cytokines, cell viability and responsible genes of glucose metabolism are susceptible to styrene, which consequently lead to other abnormalities in various organs.
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Affiliation(s)
- Kamal Niaz
- International Campus, Tehran University of Medical Sciences (IC-TUMS), Tehran, Iran; Toxicology and Diseases Group, Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Toxicology and Pharmacology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
| | - Fatima Ismail Hassan
- International Campus, Tehran University of Medical Sciences (IC-TUMS), Tehran, Iran; Toxicology and Diseases Group, Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Faheem Mabqool
- International Campus, Tehran University of Medical Sciences (IC-TUMS), Tehran, Iran; Toxicology and Diseases Group, Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Fazlullah Khan
- International Campus, Tehran University of Medical Sciences (IC-TUMS), Tehran, Iran; Toxicology and Diseases Group, Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Toxicology and Pharmacology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
| | - Saeideh Momtaz
- Medicinal Plants Research Center, Institute of Medicinal Plants, ACECR, Karaj, Iran; Toxicology and Diseases Group, Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Baeeri
- Toxicology and Diseases Group, Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mona Navaei-Nigjeh
- Toxicology and Diseases Group, Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahban Rahimifard
- Toxicology and Diseases Group, Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Abdollahi
- International Campus, Tehran University of Medical Sciences (IC-TUMS), Tehran, Iran; Toxicology and Diseases Group, Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Toxicology and Pharmacology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran.
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8
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Fetoni AR, Rolesi R, Paciello F, Eramo SLM, Grassi C, Troiani D, Paludetti G. Styrene enhances the noise induced oxidative stress in the cochlea and affects differently mechanosensory and supporting cells. Free Radic Biol Med 2016; 101:211-225. [PMID: 27769922 DOI: 10.1016/j.freeradbiomed.2016.10.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 10/03/2016] [Accepted: 10/17/2016] [Indexed: 12/20/2022]
Abstract
Experimental and human investigations have raised the level of concern about the potential ototoxicity of organic solvents and their interaction with noise. The main objective of this study was to characterize the effects of the combined noise and styrene exposure on hearing focusing on the mechanism of damage on the sensorineural cells and supporting cells of the organ of Corti and neurons of the ganglion of Corti. The impact of single and combined exposures on hearing was evaluated by auditory functional testing and histological analyses of cochlear specimens. The mechanism of damage was studied by analyzing superoxide anion and lipid peroxidation expression and by computational analyses of immunofluorescence data to evaluate and compare the oxidative stress pattern in outer hair cells versus the supporting epithelial cells of the organ of Corti. The oxidative stress hypothesis was further analyzed by evaluating the protective effect of a Coenzyme Q10 analogue, the water soluble Qter, molecule known to have protective antioxidant properties against noise induced hearing loss and by the analysis of the expression of the endogenous defense enzymes. This study provides evidence of a reciprocal noise-styrene synergism based on a redox imbalance mechanism affecting, although with a different intensity of damage, the outer hair cell (OHC) sensory epithelium. Moreover, these two damaging agents address preferentially different cochlear targets: noise mainly the sensory epithelium, styrene the supporting epithelial cells. Namely, the increase pattern of lipid peroxidation in the organ of Corti matched the cell damage distribution, involving predominantly OHC layer in noise exposed cochleae and both OHC and Deiters' cell layers in the styrene or combined exposed cochleae. The antioxidant treatment reduced the lipid peroxidation increase, potentiated the endogenous antioxidant defense system at OHC level in both exposures but it failed to ameliorate the oxidative imbalance and cell death of Deiters' cells in the styrene and combined exposures. Current antioxidant therapeutic approaches to preventing sensory loss focus on hair cells alone. It remains to be seen whether targeting supporting cells, in addition to hair cells, might be an effective approach to protecting exposed subjects.
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MESH Headings
- Animals
- Antioxidants/pharmacology
- Hair Cells, Auditory, Inner/drug effects
- Hair Cells, Auditory, Inner/metabolism
- Hair Cells, Auditory, Inner/pathology
- Hair Cells, Auditory, Outer/drug effects
- Hair Cells, Auditory, Outer/metabolism
- Hair Cells, Auditory, Outer/pathology
- Hearing Loss, Noise-Induced/metabolism
- Hearing Loss, Noise-Induced/pathology
- Hearing Loss, Noise-Induced/physiopathology
- Hearing Loss, Noise-Induced/prevention & control
- Labyrinth Supporting Cells/drug effects
- Labyrinth Supporting Cells/metabolism
- Labyrinth Supporting Cells/pathology
- Lipid Peroxidation/drug effects
- Male
- Noise/adverse effects
- Oxidation-Reduction
- Oxidative Stress
- Rats
- Rats, Wistar
- Styrene/toxicity
- Ubiquinone/analogs & derivatives
- Ubiquinone/pharmacology
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Affiliation(s)
- A R Fetoni
- Institute of Otolaryngology, Università Cattolica School of Medicine, Rome, Italy; Institute of Cell Biology and Neurobiology, CNR, Monterotondo, Italy.
| | - R Rolesi
- Institute of Otolaryngology, Università Cattolica School of Medicine, Rome, Italy
| | - F Paciello
- Institute of Otolaryngology, Università Cattolica School of Medicine, Rome, Italy; Institute of Cell Biology and Neurobiology, CNR, Monterotondo, Italy
| | - S L M Eramo
- Institute of Human Physiology, Università Cattolica School of Medicine, Rome, Italy
| | - C Grassi
- Institute of Human Physiology, Università Cattolica School of Medicine, Rome, Italy
| | - D Troiani
- Institute of Human Physiology, Università Cattolica School of Medicine, Rome, Italy
| | - G Paludetti
- Institute of Otolaryngology, Università Cattolica School of Medicine, Rome, Italy
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9
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Kumar S, Maiti P. Controlled biodegradation of polymers using nanoparticles and its application. RSC Adv 2016. [DOI: 10.1039/c6ra08641a] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Controlled biodegradation mechanism has been revealed using different nanoparticles which eventually regulate pH of media.
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Affiliation(s)
- Sunil Kumar
- School of Materials Science and Technology
- Indian Institute of Technology (Banaras Hindu University)
- Varanasi 221 005
- India
| | - Pralay Maiti
- School of Materials Science and Technology
- Indian Institute of Technology (Banaras Hindu University)
- Varanasi 221 005
- India
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10
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Morrison E, Kantz A, Gassner GT, Sazinsky MH. Structure and mechanism of styrene monooxygenase reductase: new insight into the FAD-transfer reaction. Biochemistry 2013; 52:6063-75. [PMID: 23909369 DOI: 10.1021/bi400763h] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The two-component flavoprotein styrene monooxygenase (SMO) from Pseudomonas putida S12 catalyzes the NADH- and FAD-dependent epoxidation of styrene to styrene oxide. In this study, we investigate the mechanism of flavin reduction and transfer from the reductase (SMOB) to the epoxidase (NSMOA) component and report our findings in light of the 2.2 Å crystal structure of SMOB. Upon rapidly mixing with NADH, SMOB forms an NADH → FADox charge-transfer intermediate and catalyzes a hydride-transfer reaction from NADH to FAD, with a rate constant of 49.1 ± 1.4 s(-1), in a step that is coupled to the rapid dissociation of NAD(+). Electrochemical and equilibrium-binding studies indicate that NSMOA binds FADhq ∼13-times more tightly than SMOB, which supports a vectoral transfer of FADhq from the reductase to the epoxidase. After binding to NSMOA, FADhq rapidly reacts with molecular oxygen to form a stable C(4a)-hydroperoxide intermediate. The half-life of apoSMOB generated in the FAD-transfer reaction is increased ∼21-fold, supporting a protein-protein interaction between apoSMOB and the peroxide intermediate of NSMOA. The mechanisms of FAD dissociation and transport from SMOB to NSMOA were probed by monitoring the competitive reduction of cytochrome c in the presence and absence of pyridine nucleotides. On the basis of these studies, we propose a model in which reduced FAD binds to SMOB in equilibrium between an unreactive, sequestered state (S state) and more reactive, transfer state (T state). The dissociation of NAD(+) after the hydride-transfer reaction transiently populates the T state, promoting the transfer of FADhq to NSMOA. The binding of pyridine nucleotides to SMOB-FADhq shifts the FADhq-binding equilibrium from the T state to the S state. Additionally, the 2.2 Å crystal structure of SMOB-FADox reported in this work is discussed in light of the pyridine nucleotide-gated flavin-transfer and electron-transfer reactions.
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Affiliation(s)
- Eliot Morrison
- Department of Chemistry and Biochemistry, San Francisco State University , San Francisco, California, United States
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11
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Gopal KV, Wu C, Moore EJ, Gross GW. Assessment of styrene oxide neurotoxicity using in vitro auditory cortex networks. ISRN OTOLARYNGOLOGY 2011; 2011:204804. [PMID: 23724250 PMCID: PMC3658808 DOI: 10.5402/2011/204804] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Accepted: 07/06/2011] [Indexed: 11/23/2022]
Abstract
Styrene oxide (SO) (C8H8O), the major metabolite of styrene (C6H5CH=CH2), is widely used in industrial applications. Styrene and SO are neurotoxic and cause damaging effects on the auditory system. However, little is known about their concentration-dependent electrophysiological and morphological effects. We used spontaneously active auditory cortex networks (ACNs) growing on microelectrode arrays (MEA) to characterize neurotoxic effects of SO. Acute application of 0.1 to 3.0 mM SO showed concentration-dependent inhibition of spike activity with no noticeable morphological changes. The spike rate IC50 (concentration inducing 50% inhibition) was 511 ± 60 μM (n = 10). Subchronic (5 hr) single applications of 0.5 mM SO also showed 50% activity reduction with no overt changes in morphology. The results imply that electrophysiological toxicity precedes cytotoxicity. Five-hour exposures to 2 mM SO revealed neuronal death, irreversible activity loss, and pronounced glial swelling. Paradoxical "protection" by 40 μM bicuculline suggests binding of SO to GABA receptors.
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Affiliation(s)
- Kamakshi V Gopal
- Department of Speech and Hearing Sciences, University of North Texas, P.O. Box 305010, Denton, TX 76203-5010, USA ; Center for Network Neuroscience, University of North Texas, P.O. Box 305010, Denton, TX 76203-5010, USA
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Sati PC, Khaliq F, Vaney N, Ahmed T, Tripathi AK, Banerjee BD. Pulmonary function and oxidative stress in workers exposed to styrene in plastic factory: occupational hazards in styrene-exposed plastic factory workers. Hum Exp Toxicol 2011; 30:1743-50. [PMID: 21382913 DOI: 10.1177/0960327111401436] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Styrene is a volatile organic compound used in factories for synthesis of plastic products. The pneumotoxicity of styrene in experimental animals is known. The aim of the present study was to study the effect of styrene on lung function and oxidative stress in occupationally exposed workers in plastic factory. Thirty-four male workers, between 18 and 40 years of age, exposed to styrene for atleast 8 hours a day for more than a year were studied, while 30 age- and sex-matched healthy subjects not exposed to styrene served as controls. Assessment of lung functions showed a statistically significant reduction (p < 0.05) in most of the lung volumes, capacities (FVC, FEV(1), VC, ERV, IRV, and IC) and flow rates (PEFR, MEF(75%), and MVV) in the study group (workers) as compared to controls. Malondialdehyde (MDA) was observed to be significantly high (p < 0.05) while ferric-reducing ability of plasma (FRAP) was significantly low (p < 0.05) in styrene-exposed subjects. Reduced glutathione (GSH) level was significantly depleted in exposed subjects as compared to control group. The mean value of serum cytochrome c in styrene-exposed subjects was found to be 1.1 ng/ml (0.89-1.89) while in control its levels were under detection limit (0.05 ng/ml). It shows that styrene inhalation by workers leads to increased level of oxidative stress, which is supposed to be the cause of lung damage.
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Affiliation(s)
- Prakash Chandra Sati
- Department of Physiology, University College of Medical Sciences (University of Delhi) and GTB, Delhi, India
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13
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Monzote L, Stamberg W, Staniek K, Gille L. Toxic effects of carvacrol, caryophyllene oxide, and ascaridole from essential oil of Chenopodium ambrosioides on mitochondria. Toxicol Appl Pharmacol 2009; 240:337-47. [DOI: 10.1016/j.taap.2009.08.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2009] [Revised: 07/28/2009] [Accepted: 08/03/2009] [Indexed: 10/20/2022]
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Yang WP, Hu BH, Chen GD, Bielefeld EC, Henderson D. Protective effect of N-acetyl-L-cysteine (L-NAC) against styrene-induced cochlear injuries. Acta Otolaryngol 2009; 129:1036-43. [PMID: 19051069 DOI: 10.1080/00016480802566261] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
CONCLUSION Styrene exposure causes hair cell death through both apoptotic and necrotic pathways and treatment with N-acetyl-L-cysteine (L-NAC) reduces styrene ototoxicity. OBJECTIVE Exposure to styrene causes hearing loss and hair cell death in the middle frequency region in the cochlea. The current study was designed to examine the cell death pathways and the protective effect of L-NAC against styrene-induced cochlear injuries. MATERIALS AND METHODS Seventeen rats were exposed to styrene by gavage at 400 mg/kg 5 days per week for 3 weeks. Nine of the styrene-treated rats received L-NAC by intraperitoneal injection (325 mg/kg), and the remaining eight rats received saline injections as controls. The styrene-induced hearing loss was assessed by auditory brainstem responses (ABRs). Apoptotic, necrotic, and missing hair cells were quantified using combined methods, including nuclear staining with propidium iodide, F-actin staining with FITC-phalloidin, and the TUNEL assay. RESULTS The styrene exposure caused a threshold shift of 15±4.3 dB. Both apoptosis and necrosis were involved in the pathogenesis of the cochlear lesion, but apoptosis appeared to be the major cell death pathway leading to the styrene ototoxicity. Treatment with L-NAC reduced the number of missing and dying outer hair cells (OHCs) and reduced the styrene-induced hearing loss.
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Harvilchuck JA, Pu X, Klaunig JE, Carlson GP. Indicators of oxidative stress and apoptosis in mouse whole lung and Clara cells following exposure to styrene and its metabolites. Toxicology 2009; 264:171-8. [PMID: 19666080 DOI: 10.1016/j.tox.2009.08.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Revised: 07/24/2009] [Accepted: 08/02/2009] [Indexed: 11/25/2022]
Abstract
In mice, styrene is hepatotoxic, pneumotoxic, and causes lung tumors. One explanation for the mechanism of toxicity is oxidative stress/damage. Previous studies have shown decreased glutathione levels, linked to increased apoptosis, in lung homogenates and isolated Clara cells 3 h following styrene or styrene oxide (SO) administration or in vitro exposure. The objective of the current studies was to determine what effects styrene and its active metabolites, primarily styrene oxide, had on indicators of oxidative stress and attendant apoptosis in order to understand better the mechanism of styrene-induced toxicity. Three hours following in vitro exposure of Clara cells to styrene or SO there were increases in reactive oxygen species (ROS). Following administration of styrene or styrene oxide ip, increases in ROS, superoxide dismutase (SOD), and 8-hydroxydeoxyguanosine (8-OHdG) formation were observed. Since increases in ROS have been linked to increases in apoptosis ratios of bax/bcl-2, mRNA and protein expression were determined 3-240 h following the administration of styrene and R-styrene oxide (RSO). The bax/bcl-2 mRNA ratio increased 12 and 24 h following R-SO and 120 h following styrene administration. However, the bax/bcl-2 protein ratio was not increased until 240 h following R-SO, and 24 and 240 h following styrene administration. However, only a slight increase in caspase 3 was observed. These results indicated that oxidative stress occurred 3h following styrene or styrene oxide as evidenced by increased ROS and SOD. This increased ROS may be responsible for the increased 8-OHdG formation. Our findings of limited apoptosis in Clara cells following acute exposure to styrene or SO are in agreement with others and may reflect the minimal extent to which apoptosis plays a role in acute styrene toxicity. It is clear, however, that oxidative stress and oxidative effects on DNA are increased following exposure to styrene or styrene oxide, and these may play a role in the lung tumorigenesis in mice.
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Affiliation(s)
- Jill A Harvilchuck
- School of Health Sciences, Purdue University, West Lafayette, IN 47907-2051, USA
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Hirasawa F, Kawagoe M, Arany S, Koizumi Y, Ueno Y, Sugiyama T. Styrene monomer primarily induces CYP2B1 mRNA in rat liver. Xenobiotica 2008; 35:1089-99. [PMID: 16418063 DOI: 10.1080/00498250500356373] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
To determine the cytochrome P450 (CYP) primarily expressed after styrene exposure, seven forms of hepatic CYP mRNA in rats treated with 600 mg kg(-1) styrene were examined. CYP1A2, CYP2B1/2, CYP2E1 and CYP3A2 mRNA were observed using real-time LightCycler PCR. The amount of CYP2B1 mRNA was significantly increased, 47-fold compared with controls, suggesting that this CYP is the primary cytochrome P450 in rats exposed to styrene. Significant increases in the amount of CYP2E1, CYP1A2 and CYP2B2 mRNA were also observed after styrene exposure, and their increase levels were 3.1-, 1.7- and 1.7-fold higher than controls, respectively. Western blot analysis also indicated that the protein levels of CYP2B1, CYP2B2, CYP2E1 and CYP1A2 showed clear increases after styrene treatment, corresponding to their mRNA expression. CYP2C11 mRNA decreased significantly in rats after styrene exposure. CYP1A1 was detected at the mRNA level in rat liver, but it was not detected at the protein level. The expression of epoxide hydrolase (EH), involved in Phase I drug metabolism, was also examined. EH mRNA increased 2-fold compared with controls after styrene exposure. Styrene thus appears to be a chemical compound that induces multiple CYPs. The results demonstrate that CYP2B1 is the primarily induced CYP form by styrene treatment to rats at acute toxic level.
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Affiliation(s)
- F Hirasawa
- Department of Biochemistry, Akita University School of Medicine, Japan
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Karovic O, Tonazzini I, Rebola N, Edström E, Lövdahl C, Fredholm BB, Daré E. Toxic effects of cobalt in primary cultures of mouse astrocytes. Biochem Pharmacol 2007; 73:694-708. [PMID: 17169330 DOI: 10.1016/j.bcp.2006.11.008] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Revised: 11/03/2006] [Accepted: 11/10/2006] [Indexed: 01/27/2023]
Abstract
Cobalt is suspected to cause memory deficit in humans and was reported to induce neurotoxicity in animal models. We have studied the effects of cobalt in primary cultures of mouse astrocytes. CoCl(2) (0.2-0.8mM) caused dose-dependent ATP depletion, apoptosis (cell shrinkage, phosphatidylserine externalization and chromatin rearrangements) and secondary necrosis. The mitochondria appeared to be a main target of cobalt toxicity, as shown by the loss of mitochondrial membrane potential (DeltaPsi(m)) and release from the mitochondria of apoptogenic factors, e.g. apoptosis inducing factor (AIF). Pre-treatment with bongkrekic acid reduced ATP depletion, implicating the involvement of the mitochondrial permeability transition (MPT) pore. Cobalt increased the generation of oxygen radicals, but antioxidants did not prevent toxicity. There was also an impaired response to ATP stimulation, evaluated as a lower raise in intracellular calcium. Similarly to hypoxia and dymethyloxallyl glycine (DMOG), cobalt triggered stabilization of the alpha-subunit of hypoxia-inducible factor HIF-1 (HIF-1alpha). This early event was followed by an increased expression of HIF-1 regulated genes, e.g. stress protein HO-1, pro-apoptotic factor Nip3 and iNOS. Although all of the three stimuli activated the HIF-1alpha pathway and decreased ATP levels, the downstream effects were different. DMOG only inhibited cell proliferation, whereas the other two conditions caused cell death by apoptosis and necrosis. This points to cobalt and hypoxia not only inducing HIF-1alpha regulated genes but also affecting similarly other cellular functions, including metabolism.
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Affiliation(s)
- Olga Karovic
- Department of Physiology and Pharmacology, Karolinska Institutet, S-171 77 Stockholm, Sweden
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Carelli V, Franceschini F, Venturi S, Barboni P, Savini G, Barbieri G, Pirro E, La Morgia C, Valentino ML, Zanardi F, Violante FS, Mattioli S. Grand rounds: could occupational exposure to n-hexane and other solvents precipitate visual failure in leber hereditary optic neuropathy? ENVIRONMENTAL HEALTH PERSPECTIVES 2007; 115:113-5. [PMID: 17366829 PMCID: PMC1797843 DOI: 10.1289/ehp.9245] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
CONTEXT Leber hereditary optic neuropathy (LHON) is a maternally inherited loss of central vision related to pathogenic mutations in the mitochondrial genome, which are a necessary but not sufficient condition to develop the disease. Investigation of precipitating environmental/occupational (and additional genetic) factors could be relevant for prevention. CASE PRESENTATION After a 6-month period of occupational exposure to n-hexane and other organic solvents, a 27-year-old man (a moderate smoker) developed an optic neuropathy. The patient had a full ophthalmologic and neurologic investigation, including standardized cycloergometer test for serum lactic acid levels and a skeletal muscle biopsy. His exposure history was also detailed, and he underwent genetic testing for LHON mitochondrial DNA mutations. The patient suffered a sequential optic neuropathy with the hallmarks of LHON and tested positive for the homoplasmic 11778G--> A/ND4 mutation. Routine laboratory monitoring revealed increased concentrations of urinary 2.5 hexandione (n-hexane metabolite) and hippuric acid (toluene metabolite) in the period immediately preceding the visual loss. DISCUSSION In a subject carrying an LHON mutation, the strict temporal sequence of prolonged appreciable occupational exposure followed by sudden onset of visual loss must raise a suspicion of causality (with a possible further interaction with tobacco smoke). RELEVANCE In this article, we add to the candidate occupational/environmental triggers of LHON and highlight the need for appropriate case-control (and laboratory) studies to validate the causal effect of mixed toxic exposures.
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Affiliation(s)
- Valerio Carelli
- Dipartimento di Scienze Neurologiche, Alma Mater Studiorum—University of Bologna, Bologna, Italy
| | - Flavia Franceschini
- Dipartimento di Sanità Pubblica, Azienda USL Bologna, San Giorgio di Piano, Bologna, Italy
| | - Silvia Venturi
- U.O. Medicina del Lavoro, Policlinico S.Orsola-Malpighi, Alma Mater Studiorum—University of Bologna, Bologna, Italy
| | | | | | - Giuseppe Barbieri
- Dipartimento di Sanità Pubblica, Azienda USL Bologna, San Giorgio di Piano, Bologna, Italy
| | - Ettore Pirro
- Dipartimento di Scienze Neurologiche, Alma Mater Studiorum—University of Bologna, Bologna, Italy
| | - Chiara La Morgia
- Dipartimento di Scienze Neurologiche, Alma Mater Studiorum—University of Bologna, Bologna, Italy
| | - Maria L. Valentino
- Dipartimento di Scienze Neurologiche, Alma Mater Studiorum—University of Bologna, Bologna, Italy
| | - Francesca Zanardi
- U.O. Medicina del Lavoro, Policlinico S.Orsola-Malpighi, Alma Mater Studiorum—University of Bologna, Bologna, Italy
| | - Francesco S. Violante
- U.O. Medicina del Lavoro, Policlinico S.Orsola-Malpighi, Alma Mater Studiorum—University of Bologna, Bologna, Italy
| | - Stefano Mattioli
- U.O. Medicina del Lavoro, Policlinico S.Orsola-Malpighi, Alma Mater Studiorum—University of Bologna, Bologna, Italy
- Address correspondence to S. Mattioli, Laboratorio di Epidemiologia, UO Medicina del Lavoro, Università di Bologna, Policlinico S. Orsola-Malpighi, via Pelagio Palagi, 9, 40138 Bologna, Italy. Telephone: 39-051-636-2932. Fax 39-051-636-2609. E-mail:
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Carlson GP, Turner M, Mantick NA. Effects of styrene and styrene oxide on glutathione-related antioxidant enzymes. Toxicology 2006; 227:217-26. [PMID: 16971035 DOI: 10.1016/j.tox.2006.08.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2006] [Revised: 08/01/2006] [Accepted: 08/03/2006] [Indexed: 11/22/2022]
Abstract
Styrene is both hepatotoxic and pneumotoxic in mice. Its mode of action is not clear, but it may be related to oxidative stress including a very large decrease in reduced glutathione (GSH). The current studies evaluated if: (1) the more toxic R-styrene oxide had a greater effect on reduced GSH levels than the less toxic S-styrene oxide, (2) the ratio of reduced to oxidized forms of glutathione was altered by styrene or styrene oxide, (3) other enzymes involved in the oxidant status of the cell, namely glutathione reductase, glutathione peroxidase and gamma-glutamylcysteine synthetase were altered, and (4) lipid peroxidation, as measured by the determination of malondialdehyde, increased. R-Styrene oxide (300mg/kg, ip) caused greater decreases in mouse liver and lung GSH than did S-styrene oxide (300mg/kg, ip). Styrene (600mg/kg, ip) caused decreases in both GSH and GSSG in both liver and lung. Styrene and styrene oxide did not cause significant increases in lipid peroxidation in either liver or lung. Styrene and styrene oxide had minimal effects on glutathione reductase and glutathione peroxidase in liver and lung. Styrene increased gamma-glutamylcysteine synthetase activity. The results suggest that while styrene and its metabolite styrene oxide cause significant decreases in GSH levels, they have little effect on the enzymes glutathione reductase and glutathione peroxidase and that in response to decreased glutathione levels there is an increase in its synthesis via induction of gamma-glutamylcysteine synthetase activity.
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Affiliation(s)
- Gary P Carlson
- School of Health Sciences, Purdue University, West Lafayette, IN 47907, USA.
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Vettori MV, Caglieri A, Goldoni M, Castoldi AF, Darè E, Alinovi R, Ceccatelli S, Mutti A. Analysis of oxidative stress in SK-N-MC neurons exposed to styrene-7,8-oxide. Toxicol In Vitro 2005; 19:11-20. [PMID: 15582351 DOI: 10.1016/j.tiv.2004.04.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2003] [Accepted: 04/28/2004] [Indexed: 10/26/2022]
Abstract
Styrene-7,8-oxide (SO) is the main metabolite of styrene, a neurotoxic volatile organic compound used industrially. Here we report the novel observation that several markers of oxidative stress were affected in SK-N-MC cells exposed for 16 h to concentrations of SO that induce apoptotic cell death. The production of Thiobarbituric Acid Reactive Substances (TBARS), rose from 69.1 +/- 15.7 nmol/g protein (control) to 119.3 +/- 39.2 and 102.0 +/- 17.3 nmol/g protein after exposure to 0.3 and 1 mM SO, respectively. Carbonyl group levels were significantly enhanced by SO at both concentrations. The lower dose also decreased sulphydryl groups. SO caused a marked oxidative DNA damage, as shown by a fivefold increase in 8-hydroxy-2(')-deoxyguanosine (8-OHdG). In addition, SO exposure resulted in alterations of scavenging abilities, given the reduction of both glutathione (GSH) and glutathione-S-transferase (GST) activity. Induction of expression of the oxidative stress response gene heme-oxygenase-1 (HO-1) and an increased HO-1 activity were also observed. These data provide compelling evidence that oxidative stress significantly contributes to SO toxicity in neuronal cells.
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Affiliation(s)
- M V Vettori
- ISPESL Research Center at the University of Parma, via Gramsci 14, Parma 43100, Italy.
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