Evaluation on Effects of Hexabromocyclododecane on Acetylcholinesterase and Oxidative Stress in the Brain of Juvenile Crimson Snapper (Lutjanus erythopterus)

Key words: 
• hexabromocyclododecane /
• Lutjanus erythopterus /
• acetylcholinesterase /
• oxidative stress /
• integrated biomarker responses index (IBR)

Abstract: Hexabromocyclododecane (C₁₂H₁₈Br₆, HBCD) has recently become the priority pollutant and the high production volume chemical due to its persistence in environment. In this study, we evaluated the potential oxidative damage and neurotoxicity of different concentrations of HBCD solutions (8.6 μg·L^-1, 43.0 μg·L^-1 and 215 μg·L^-1) on brain tissues of juvenile crimson snapper (Lutjanus erythopterus). Both nonspecific biomarkers, including SOD, GST and MDA, and specific biomarkers (e.g., AChE) were selected. The stress level and toxic effects of HBCD were also evaluated using the integrated biomarker responses index (IBR). We found that the effects of HBCD on SOD and GST activities of brain tissues were different. SOD activities were positively related with the HBCD concentration during the early exposure period, but negatively related under prolonged exposure time. MDA contents and AChE activities were induced or inhibited after adding HBCD and the effects were dose-dependent. For low-dose groups, MDA contents dropped significantly at first and then increased significantly, while AChE activities showed the opposite process. For medium-dose groups, both MDA contents and AChE activities were induced. For high-dose groups, MDA contents increased significantly at first and then dropped significantly, while AChE activities showed the opposite process. The IBR analysis showed that the stress sensitivity of four kinds of biomarkers to HBCD solutions was ranked as:SOD > GST > AChE > MDA. The stress effects under medium and high concentrations were much stronger than those under other concentrations.