Zeng Lin, Ai Chun-Xiang, Wang Yong-Hong, Zhang Jian-She, Wu Chang-Wen
National Engineering Research Center for Marine Aquaculture, Zhejiang Ocean University, Zhoushan, 316000, China.
College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361005, China.
Fish Physiol Biochem. 2017 Aug;43(4):955-964. doi: 10.1007/s10695-016-0334-z. Epub 2017 Jun 14.
The aim of the present study was to evaluate the effects of abrupt salinity stress (12, 26 (control), and 40) on lipid peroxidation, activities and mRNA levels of antioxidant enzymes (Cu/Zn-SOD, CAT, GPx, and GR), and gene expression of the Nrf2-Keap1 signaling molecules at different times (6, 12, 24, and 48 h) in the liver of large yellow croaker Pseudosciaena crocea. The results showed that lipid peroxidation was sharply reduced at 6 h and increased at 12 h before returning to control levels in the hypo-salinity group. Similarly, lipid peroxidation was significantly decreased at 6 h followed by a sharp increase towards the end of the exposure in the hyper-salinity group. Negative relationships between lipid peroxidation and antioxidant enzyme activities and positive relationships between activities and gene expression of antioxidant enzymes were observed, suggesting that the changes at molecular levels and enzyme activity levels may provide protective roles against damage from salinity stress. Obtained results also showed a coordinated transcriptional regulation of antioxidant genes, suggesting that Nrf2 is required for regulating these genes. Furthermore, there was a positive relationship between the mRNA levels of Nrf2 and Keap1, indicating that Keap1 plays an important role in switching off the Nrf2 response. In conclusion, this is the first study to elucidate effects of salinity stress on antioxidant responses in large yellow croaker through the Keap1-Nrf2 pathway.
本研究旨在评估突然的盐度胁迫（12、26（对照）和40）对大黄鱼（Pseudosciaena crocea）肝脏在不同时间点（6、12、24和48小时）脂质过氧化、抗氧化酶（铜/锌超氧化物歧化酶、过氧化氢酶、谷胱甘肽过氧化物酶和谷胱甘肽还原酶）活性及mRNA水平，以及Nrf2-Keap1信号分子基因表达的影响。结果表明，低盐度组脂质过氧化在6小时时急剧降低，12小时时升高，之后恢复到对照水平。同样，高盐度组脂质过氧化在6小时时显著降低，在暴露结束时急剧升高。观察到脂质过氧化与抗氧化酶活性呈负相关，抗氧化酶活性与基因表达呈正相关，这表明分子水平和酶活性水平的变化可能对盐度胁迫造成的损伤起到保护作用。所得结果还显示抗氧化基因存在协同转录调控，表明Nrf2是调控这些基因所必需的。此外，Nrf2和Keap1的mRNA水平呈正相关，表明Keap1在关闭Nrf2反应中起重要作用。总之，这是首次通过Keap1-Nrf2途径阐明盐度胁迫对大黄鱼抗氧化反应影响的研究。
