title: 2-Chlorophenol induced hydroxyl radical production in mitochondria in Carassius auratus and oxidative stress--an electron paramagnetic resonance study.
abstract: In our previous study, electron paramagnetic resonance (EPR) evidence of reactive oxygen species (ROS) production in Carassius auratus following 2-chlorophenol (2-CP) administration was provided. To further investigate the potential pathway of ROS production, liver mitochondria of C. auratus was isolated and incubated with 2-CP for 30 min. An EPR analysis indicated ROS was produced, and intensities of ROS increased with increasing concentrations of 2-CP. The ROS was then assigned OH by comparing with Fenton reaction. Either catalase or superoxide dismutase, extinguished OH completely in the mitochondria mixture. These facts suggested that O2(.-) and H2O2 contributed to the formation of OH in mitochondria in C. auratus stressed by 2-CP. Combining previous references and our own data, it is reasonable to suggest that 2-CP is first oxidized by H2O2 present in vivo to form phenoxyl radical under the catalytic action of cellular peroxidase (1); phenoxyl radical oxidizes mitochondria NADH to NAD in the presence of NADH (2); NAD reacts with oxygen in vivo to produce O2(.-) (3); O2(.-) is spontaneously dismutated by SOD to form H2O2 and O2, which creates a renewable supply of H2O2 as the initiators of the chain reactions until NADH is consumed (4); simultaneously with reaction (4), O2(.-) reacts with H2O2 to form OH radical via the Haber-Weiss reaction (5). A strong negative correlation (r=-0.9278, p<0.01) between glutathione (GSH) pool and OH production was observed after fish were i.p. injected with 2-CP (250 mg kg(-1)), indicating the depletion of GSH caused by OH.
authors.affiliation: Tianjin Key Laboratory of Remediation and Pollution Control for Urban Ecological Environment, College of Environmental Sciences and Engineering, Nankai University, Tianjin 300071, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Luo
authors.forename: Yun-xia
authors.initials: YX
authors.lastname: Sui
authors.forename: Xiao-rong
authors.initials: XR
authors.lastname: Wang
authors.forename: Yuan
authors.initials: Y
authors.lastname: Tian
mesh_terms: D000818:Animals; D002733:Chlorophenols / Q000633:toxicity*; D004578:Electron Spin Resonance Spectroscopy; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods*; D005978:Glutathione / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D006054:Goldfish / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000737:chemistry; D017665:Hydroxyl Radical / Q000378:metabolism*; D007501:Iron / Q000737:chemistry; D008054:Lipid Peroxides / Q000378:metabolism; D008930:Mitochondria, Liver / Q000187:drug effects* / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D002733:Chlorophenols; C045076:Fenton's reagent; D008054:Lipid Peroxides; D014874:Water Pollutants, Chemical; D017665:Hydroxyl Radical; D006861:Hydrogen Peroxide; D007501:Iron; D005982:Glutathione Transferase; D005978:Glutathione; C030683:2-chlorophenol