title: Comparison of PBDE congeners as inducers of oxidative stress in zebrafish.
abstract: A proposed primary pathway through which polybrominated diphenyl ethers (PBDEs) disrupt normal biological functions is oxidative stress. In the present study, 4 PBDE congeners were evaluated for their potential to initiate oxidative stress in zebrafish during development: BDE 28, BDE 47, BDE 99, and BDE 100. N-acetylcysteine (NAC) was used to increase intracellular glutathione concentrations and only decreased the effects of BDE 28 at 10 ppm and 20 ppm and BDE 47 at 20 ppm. N-acetylcysteine coexposure did not alter the rates of mortality or curved body axis compared with PBDE exposure alone. The activity of glutathione-S-transferase (GST) was not altered at 24 h postfertilization (hpf), but increased following 10 ppm BDE 28 exposure at 120 hpf. Transcription of several genes associated with stress was also evaluated. At 24 hpf, cytochrome c oxidase subunit 6a (COX6a) transcription was up-regulated in embryos exposed to BDE 99, and BDE 28 exposure up-regulated the transcription of Glutathione-S-transferase-pi (GSTpi). At 24 hpf, glutamate-cysteine ligase (GCLC) was slightly down-regulated by all congeners evaluated. At 120 hpf, TNF receptor-associated protein 1 (TRAP1) and COX6A were up-regulated by all congeners, however GSTpi was down-regulated by all congeners. The results of quantitative real-time transcription polymerase chain reaction are mixed and do not strongly support a transcriptional response to oxidative stress. According to the authors' data, PBDEs do not induce oxidative stress. Oxidative stress may occur at high exposure concentrations; however, this does not appear to be a primary mechanism of action for the PBDE congeners tested.
authors: Department of Biology, Baylor University, Waco, Texas, USA.
authors: Crystal Y
authors: CY
authors: Usenko
authors: Erika L
authors: EL
authors: Abel
authors: Molly
authors: M
authors: Kudela
authors: Annie
authors: A
authors: Janise
authors: Erica D
authors: ED
authors: Bruce
mesh_terms: D000111:Acetylcysteine / Q000633:toxicity; D000818:Animals; D015536:Down-Regulation / Q000187:drug effects; D003576:Electron Transport Complex IV / Q000378:metabolism; D005721:Glutamate-Cysteine Ligase / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D051549:Glutathione S-Transferase pi / Q000378:metabolism; D055768:Halogenated Diphenyl Ethers / Q000737:chemistry / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects*; D011075:Polybrominated Biphenyls / Q000633:toxicity; D047990:TNF Receptor-Associated Factor 1 / Q000378:metabolism; D018675:Toxicity Tests; D015854:Up-Regulation / Q000187:drug effects; D015027:Zebrafish / Q000254:growth & development / Q000378:metabolism*
chemical_list: C477694:2,2',4,4',5-brominated diphenyl ether; D055768:Halogenated Diphenyl Ethers; D011075:Polybrominated Biphenyls; D047990:TNF Receptor-Associated Factor 1; C517827:pentabrominated diphenyl ether 100; C511295:2,2',4,4'-tetrabromodiphenyl ether; D003576:Electron Transport Complex IV; D051549:Glutathione S-Transferase pi; D005721:Glutamate-Cysteine Ligase; D005978:Glutathione; C533760:tribromodiphenyl ether 28; D000111:Acetylcysteine
keywords: Neurotoxicity; Oxidative stress; Polybrominated diphenyl ether; Zebrafish