title: Neurobehavioral toxicity of carbon nanotubes in mice.
abstract: OBJECTIVE
  The aim of this study was to evaluate neurobehavioral toxicity of single-walled (SWNTs) and multiwalled carbon nanotubes (MWNTs) in mice.
  
  
  METHODS
  Male NMRI mice were randomized into 5 groups ( n = 10 each): Normal control (NC) group was injected intraperitoneally (i.p.) with phosphate-buffered saline (PBS) solution (pH 7.8; ca. 1 mL), MW80 and MW800 groups were injected with either i.p. 80 or 800 mg kg-1MWNTs suspended in 1 mL of PBS and SW80 and SW800 groups were injected with either i.p. 80 or 800 mg kg-1SWNTs suspended in 1 mL of PBS. After 2 weeks, five mice from each group were evaluated for brain-derived neurotrophic factor (BDNF) messenger RNA expression and protein content of brain tissues. Locomotion, anxiety, learning and memory, and depression were measured by open field test (OFT), elevated plus-maze (EPM), object recognition test (ORT), and forced swimming test (FST), respectively.
  
  
  RESULTS
  Ambulation time and center arena time in the OFT did not change among groups. In the EPM paradigm, SWNTs (800 mg kg-1) and MWNTs (80 and 800 mg kg-1) showed an anxiogenic effect. In ORT, MWNTs (80 mg kg-1) increased the discrimination ratio while in FST, MWNTs showed a depressant effect as compared to vehicle. The BDNF gene expression in mice treated with 80 and 800 mg kg-1SWNTs or 80 mg kg-1MWNTs decreased as compared to NC mice although BDNF gene expression increased in mice that were treated with 800 mg kg-1MWNTs. The whole brain BDNF protein content did not change among groups.
  
  
  CONCLUSIONS
  Our study showed that i.p. exposure to carbon nanotubes (CNTs) may result in behavioral toxicity linked with expression of depression or anxiety that depends on the type of CNTs. In addition, exposure to CNTs changed BDNF gene expression.
authors.affiliation: 1 Department of Pharmacology, School of Pharmacy, Kermanshah University of Medical Sciences, Kermanshah, Islamic Republic of Iran.|2 Department of Pharmacology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Islamic Republic of Iran.
authors.forename: Babak
authors.initials: B
authors.lastname: Gholamine
authors.affiliation: 3 Department of Basic Veterinary Sciences, Laboratory of Molecular and Cellular Biology, Faculty of Veterinary Medicine, Razi University, Kermanshah, Islamic Republic of Iran.|4 Department of Biology, Faculty of Science, Razi University, Kermanshah, Islamic Republic of Iran.
authors.forename: Isaac
authors.initials: I
authors.lastname: Karimi
authors.affiliation: 1 Department of Pharmacology, School of Pharmacy, Kermanshah University of Medical Sciences, Kermanshah, Islamic Republic of Iran.
authors.forename: Amir
authors.initials: A
authors.lastname: Salimi
authors.affiliation: 3 Department of Basic Veterinary Sciences, Laboratory of Molecular and Cellular Biology, Faculty of Veterinary Medicine, Razi University, Kermanshah, Islamic Republic of Iran.
authors.forename: Parisa
authors.initials: P
authors.lastname: Mazdarani
authors.affiliation: 5 Department of Psychology and Neuroscience, University of Evansville, Evansville, IN, USA.
authors.forename: Lora A
authors.initials: LA
authors.lastname: Becker
mesh_terms: D000818:Animals; D021461:Animals, Outbred Strains; D001007:Anxiety / Q000209:etiology; D001522:Behavior, Animal / Q000187:drug effects; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D019208:Brain-Derived Neurotrophic Factor / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D003863:Depression / Q000209:etiology; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects*; D007274:Injections, Intraperitoneal; D007859:Learning Disabilities / Q000209:etiology; D008297:Male; D008569:Memory Disorders / Q000209:etiology; D051379:Mice; D037742:Nanotubes, Carbon / Q000737:chemistry / Q000633:toxicity* / Q000648:ultrastructure; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D020258:Neurotoxicity Syndromes / Q000209:etiology* / Q000503:physiopathology; D012333:RNA, Messenger / Q000378:metabolism*; D011897:Random Allocation; D023382:Toxicity Tests, Acute
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D037742:Nanotubes, Carbon; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger
keywords: Carbon nanotubes; anxiety; brain-derived neurotrophic factor; depression; locomotor; memory