Electron paramagnetic resonance investigation of in vivo free radical formation and oxidative stress induced by 2,4‐dichlorophenol in the freshwater fishCarassius auratus

Abstract

In the present study, electron paramagnetic resonance coupled with spin-trapping technique was used, with alpha-phenyl-N-tert-butylnitrone (PBN) as a spin-trapping agent, to investigate free radical generation in freshwater fish with acute 2,4-dichlorophenol (2,4-DCP) poisoning. The PBN-radical adducts were detected in fish liver samples following treatments of 2,4-DCP (0.025, 0.05, 0.5, 5, or 25 mg/kg) 24 h after intraperitoneal (i.p.) injection and 2,4-DCP (0.5 mg/kg) at 2, 4, 8, 24, or 72 h after i.p. injection in Carassius auratus. The hyperfine splitting constants for the PBN-radical adducts are aN = 13.7 G, aH = 1.8 G, and g = 2.0058, which is consistent with those of PBN/hydroxyl radical (*OH). The results indicate that the hydroxyl radical is probably produced during acute intoxication of 2,4-DCP. The relative similarity in the kinetics (from 2 to 72 h) of superoxide dismutase activity induction and *OH generation implies that the generation of *OH possibly depends on the superoxide anion (O2*-). Superoxide anion (O2*-) might be the precursor radical undergoing the Haber-Weiss reaction to form *OH. Possible pathways for radical chain reactions in the formation of the hydroxyl radical in vivo after 2,4-DCP administration are proposed. Other parameters with respect to antioxidant defense (e.g., superoxide dismutase and catalase) and oxidative damage (lipid peroxidation level) indicate that the fish were subjected to oxidative stress induced by 2,4-DCP and that the mechanisms of oxidative stress possibly involve the in vivo stimulation of hydroxyl radical formation.

The hydroxyl radical generation and oxidative stress for the earthworm Eisenia fetida exposed to tetrabromobisphenol A

“…The characteristics of radical adducts can be identified from their hyperfine splitting constants recorded on the EPR spectrum. As reported, the • OH can be significantly induced by 2,4-dichlorophenol, TBBPA, naphthalene and phenanthrene in fish liver (Luo et al 2005;Shi et al 2005a;Shi et al 2005b;Sun et al 2006;Yin et al 2007). However, it has not been reported whether TBBPA can induce SOD superoxide dismutase, CAT catalase, GST glutathione-S-transferase, GSH reduced glutathione, GSSG oxidized glutathione, GSH/GSSG ratio of reduced glutathione and oxidized glutathione Significant different from control are indicated as * P \ 0.05, ** P \ 0.01 ROS and oxidative stress in earthworm species.…”

“…Many studies argued that the GSH/ GSSG ratio was a good indicator for the level of oxidative stress (Halliwell and Gutteridge 1999;Lange et al 2002). Luo et al (2005) also reported a decrease in GSH/ GSSG ratio in fish liver exposed to 2-chlorophenol. In our study, the GSH/GSSG ratio was noted to have a significant decline at 0.1-1.0 mg L -1 TBBPA ( Table 1), suggesting that the oxidative damage occurs in the earthworms.…”

“…Recent studies suggested that TBBPA might induce oxidative stress in aquatic organisms through the generation of ROS (Luo et al 2005;Ronisz et al 2004;Shi et al 2005a;Shi et al 2005b;Sun et al 2008). TBBPA-treated rats showed a decrease of GSH level and an increase of the malondialdehyde (MDA), a product of lipid peroxidation (Szymanska et al 2000).…”

Time-Effect Relationship of Toxicity Induced by Roundup® and Its Main Constituents in Liver of Carassius Auratus

“…A six line spectrum of three groups with two hyperfine coupling splitting peaks was observed. According to previous literature [4,5,13,16], the trapped ROS was likely to be the hydroxyl radical (·OH) and the levels could be expressed with the second couplet intensity of the triplets in the EPR spectra. Figure 2 showed the kinetics of ·OH generation over Considering the speed and the maximum of ·OH accumulation, POEA is supposed to be more toxic than the other two substances.…”

“…Researches suggest that reactive oxygen species (ROS), can be induced in organisms exposed to some environmental contaminants [4][5][6]. Recent study suggested that Roundup® might induce oxidative stress in aquatic organisms through the increased levels of tissue lipid hydroperoxides [7].…”