title: Rubber additives induce oxidative stress in rainbow trout.
abstract: Several studies have demonstrated the toxicity of rubber leachate, mainly from rubber tires, to aquatic organisms. In the present study rainbow trout (Oncorhynchus mykiss) were exposed to water provided to aquaria through a rubber hose. Increased hepatic ethoxyresorufin-O-deethylase (EROD) activity, and glutathione reductase (GR) activity were observed in the exposed fish. Two common rubber additives, 2-mercaptobenzothiazole (MBT) and diphenylamine (DPA) and structurally related compounds, were identified by chemical analyses of water samples as were hydroxylated polycyclic aromatic hydrocarbons. Metabolites of these compounds were also detected in the bile of exposed fish, as were some of the parent compounds. In a following experiment, we injected rainbow trout with DPA or MBT. Both compounds affected total glutathione (tGSH) concentration in liver and MBT caused an increase in hepatic GR and glutathione S-transferase (GST) activity as well. In DPA injected fish, hydroxylated DPA was the main metabolite in the bile. Our results indicate that rubber chemicals may leach into the water surroundings where they can be taken up and metabolised by fish. Some of these chemicals can lead to up-regulation of antioxidant defences as demonstrated with DPA and MBT injections.
authors.affiliation: Department of Zoology/Zoophysiology, Göteborg University, Box 463, SE-405 30 Göteborg, Sweden. eirikur@lyf.is
authors.forename: Eiríkur
authors.initials: E
authors.lastname: Stephensen
authors.forename: Margaretha
authors.initials: M
authors.lastname: Adolfsson-Erici
authors.forename: Mats
authors.initials: M
authors.lastname: Hulander
authors.forename: Jari
authors.initials: J
authors.lastname: Parkkonen
authors.forename: Lars
authors.initials: L
authors.lastname: Förlin
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D052160:Benzothiazoles; D019363:Cytochrome P-450 CYP1A1 / Q000378:metabolism; D004159:Diphenylamine / Q000633:toxicity*; D008401:Gas Chromatography-Mass Spectrometry; D005978:Glutathione / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D017686:Oncorhynchus mykiss / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects*; D011084:Polycyclic Aromatic Hydrocarbons / Q000633:toxicity*; D012408:Rubber / Q000737:chemistry*; D013844:Thiazoles / Q000633:toxicity*
chemical_list: D052160:Benzothiazoles; D011084:Polycyclic Aromatic Hydrocarbons; D013844:Thiazoles; C005563:captax; D012408:Rubber; D004159:Diphenylamine; D019363:Cytochrome P-450 CYP1A1; D005980:Glutathione Reductase; D005982:Glutathione Transferase; D005978:Glutathione