Acute temperature changes induce an oxidative stress response in kidney cells of grass carp Ctenopharyngodon idellus.

Recent studies on the effects of temperature on the antioxidant system of fish have been conducted mostly in vivo. In vivo experimental results are influenced by many factors, and can vary widely. Hence, experiments at the cellular level can provide a new direction for scientific research. The purpose of this study was to investigate the mechanism of the antioxidant system in response to temperature changes in grass carp Ctenopharyngodon idellus kidney (CIK) cells. CIK cells were exposed to culture temperatures of 20 °C, 24 °C, 28 °C, 32 °C, and 36 °C for 24 h, and the results showed that heat stress significantly increased the level of reactive oxygen species (ROS), which further led to increased content of malondialdehyde (MDA) and protein carbonyl. The increase of the ratio of Rh123 fluorescence indicated a decrease in mitochondrial membrane potential ( Δ Ψ m ), demonstrating that the changes in temperature destroyed the mitochondrial membrane of CIK cells. The acute temperature stress increased the activity of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), and glutathione reductase (GR), and improved total antioxidant capacity (TAC) and glutathione (GSH). The relative mRNA expression levels of Cu–Zn sod, gpx, and cat were significantly increased with the variation in temperature. In conclusion, the changes in temperature disturbed the homeostasis of the CIK cells, destroyed the mitochondrial membrane, and enhanced the activity of major antioxidant enzymes to resist oxidative stress. [ABSTRACT FROM AUTHOR]