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Cu pre-exposure alters antioxidant defense and energy metabolism in large yellow croaker Larimichthys crocea in response to severe hypoxia

Zeng, Lin, Ai, Chun-Xiang, Zheng, Jia-Lang, Zhang, Jian-She, Li, Wen-Cheng
The Science of the total environment 2019 v.687 pp. 702-711
Larimichthys crocea, anaerobiosis, antioxidant activity, copper, fish, genes, histology, hypoxia-inducible factor 1, liver, mortality, reactive oxygen species, synergism, transcription (genetics), vacuoles
The aim of the present study was to evaluate the effects of Cu pre-exposure on antioxidant defense and energy metabolism in the liver of the large yellow croaker exposed to severe hypoxia. Fish were pre-acclimated to 0 and 30 μg Cu L−1 for 96 h, and subsequently exposed to 7.0 and 1.5 mg DO L−1 for another 24 h. Hypoxic stress alone increased reactive oxygen species and hepatic vacuoles. When compared to hypoxic stress alone, hypoxic stress plus Cu pre-exposure increased mortality and ROS production, and worsened histological structure by inhibiting antioxidant defense and aerobic metabolism, and enhancing anaerobic metabolism, suggesting Cu pre-acclimation aggravated hypoxia-induced oxidative damage. NFE2-related nuclear factor 2 and hypoxia-inducible factor-1α might participate in the transcriptional regulation of genes related to antioxidant response and energy metabolism, respectively. In conclusion, Cu pre-acclimation had a synergistic effect on antioxidant response and energy metabolism in fish under severe hypoxia, which contributes to understanding the molecular mechanisms underlying negative effects of Cu pre-acclimation against hypoxic damage in fish.