W3 PM Biomarkers
Wednesday, 16 November 2005: 1:50 PM - 5:30 PM in Ballroom 3

(WAN-1117-796742) ROS generation and its mediated oxidative damage induced by the chemical pollutants.

Wang, X¹, Luo, Y¹, Shi, H¹, Ji, L², ¹ Nanjing University, Nanjing, China² Liaoning University, Shenyang, China

ABSTRACT- Five structurally different chemicals such as Nap, 2,4-DCP, 2,4-DNP, phenanthrene and Cd were selected to investigate their potential to induced the Reactive Oxygen Species (ROS) and the subsequent oxidative damage in fish C. auratus. Spin trapping technique followed by paramagnetic resonance (EPR) analysis, with a-phenyl-N-tert-butylnitrone (PBN) as a spin trapping agent to test the potential of ROS production in liver of fish after exposure of Nap, phenanthrene, 2,4-DNP, Cd and 2,4-DCP i.p injection and Results showed that ROS was produced after the treatments respectively, and subsequent oxidative damage, e.g. LPO and PCO were observed with dose-dependent manner after Nap, 2,4-DCP and Cd treatment. After EPR spectrum analysis, the reactive oxygen species which were trapped by PBN was probably the hydroxyl radical. Then, a more reliable technique to identify the hydroxyl radical named secondary radical spin trapping technique was used which PBN was dissolved in DMSO to trap hydroxyl radical generation in C. auratus after Tetrabromobisphenol A (TBBPA) i.p. injection. If hydroxyl radical was produced, it can react with DMSO to form methyl radical and then trapped by PBN which was recorded from EPR spectrum. Results confirmed hydroxyl radical was formed in liver and bile of fish and showed a dose- and time-dependent increase with TBBPA post-i.p. injection. The possible mechanisms of hydroxyl radical production after 2,4-DCP i.p. injection was proposed from the relative similarity in the kinetics (from 2 h to 72 h) of SOD activity induction and hydroxyl radical generation which implies that the generation of hydroxyl radical possibly depends on the superoxide anion. superoxide anion might be the precursor radical undergoing the Haber-Weiss reaction to form hydroxyl radical. All of these results provide the direct evidence of the enhancement of hydroxyl radical generation stimulated by the chemical pollutants. Hydroxyl radical is the most reactive oxygen species and may contribute to serious molecular damage in the living systems, which had been confirmed by our results. Our results suggest one of the important mechanisms of toxicity of some chemical pollutants in water body is the pro-oxidant derived reactive oxygen species production and the subsequent oxidative damage.

Key words: ROS, EPR, Hydroxyl radical, Oxidative damage