Free radical generation and lipid peroxidation induced by 2,4-dichlorophenol in liver of Carassius auratus

Free radical generation in liver of larval fish (Carassius auratus) after 2,4-dichlorophenol (2,4-DCP) injected intraperitoneally 24 h was studied with electron paramagnetic resonance (EPR) spin trapping technique and α-phenyl-N-tertbutylnitrone (PBN) as spin trap reagent. The results show that there is a significant increase of free radical generation in the liver of the fish treated with 2,4-DCP (0.025, 0.05, 0.5, 5, 25 mg/kg) compared with that of the control (p<0.05). The free radical generation correlates well with the dose of 2,4-DCP administered. The regress equation for dose-effect relation is y=1189ln(x) + 9220, r²=0.9856. The six-line composed of three groups with two hyperfine splitting peaks in each shows a typical PEN/-OH EPR spectrum. The hyperfine splitting constants for the PBN-adducts is aN=13.7 Gauss, aH=1.8 Gauss, g factor is 2.0058, which is consistent with the characteristics of PBN-hydroxyl radical adduct reported from the literature. Results also show that there is a significant increase for malondialdehyde (MDA) content in the treated groups compared with that of the control (p<0.05). The mechanisms of free radical generation and lipid peroxidation induced by 2,4-DCP are discussed in this study.