Hypoxic acclimation improves mitochondrial bioenergetic function in large yellow croaker Larimichthys crocea under Cu stress

Lin Zeng; Wen-Cheng Li; Hui Zhang; Ping Cao; Chun-Xiang Ai; Bing Hu; Wei Song

doi:10.1016/j.ecoenv.2021.112688

Hypoxic acclimation improves mitochondrial bioenergetic function in large yellow croaker Larimichthys crocea under Cu stress

Ecotoxicol Environ Saf. 2021 Aug 20:224:112688. doi: 10.1016/j.ecoenv.2021.112688. Online ahead of print.

Authors

Lin Zeng¹, Wen-Cheng Li¹, Hui Zhang¹, Ping Cao², Chun-Xiang Ai³, Bing Hu⁴, Wei Song⁵

Affiliations

¹ National Engineering Research Center of Marine Facilities Aquaculture, Zhejiang Ocean University, Zhoushan 316022, PR China.
² East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai 200090, PR China.
³ College of Ocean and Earth Sciences, Xiamen University, Xiamen 361005, PR China. Electronic address: chunxai@xmu.edu.cn.
⁴ Fujian Province Key Laboratory of Special Aquatic Formula Feed, Fuqing 350300, PR China.
⁵ National Engineering Research Center of Marine Facilities Aquaculture, Zhejiang Ocean University, Zhoushan 316022, PR China; East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai 200090, PR China. Electronic address: songw@ecsf.ac.cn.

PMID: 34425539
DOI: 10.1016/j.ecoenv.2021.112688

Abstract

The purpose of this study was to investigate how pre-hypoxia exposure affected the mitochondrial structure and bioenergetic function of large yellow croaker in responding to Cu stress. Fish were acclimated to normoxia and 3.0 mg DO L^-1 for 48 h, then subjected to 0 and 120 μg Cu L^-1 for another 48 h. Hypoxic acclimation did not affect mitochondrial ultrastructure and reactive oxygen species (ROS), but reduced oxidative phosphorylation (OXPHOS) efficiency. Cu exposure impaired mitochondrial ultrastructure, increased ROS generation and inhibited OXPHOS efficiency. Compared with Cu exposure alone, hypoxic acclimation plus Cu exposure reduced ROS production and improved OXPHOS efficiency by enhancing mitochondrial respiratory control ratio, mitochondrial membrane potential, and activities and gene expressions of electron transport chain enzymes. In conclusion, hypoxic acclimation improved the mitochondrial energy metabolism of large yellow croaker under Cu stress, facilitating our understanding of the molecular mechanisms regarding adaptive responses of hypoxia-acclimated fish under Cu stress.

Keywords: Cu exposure; Hypoxic acclimation; Mitochondria; Oxidative phosphorylation.