Effects of Zn2+ stress on expression of key antioxidant genes and antioxidant enzyme activities in eckloni naked carp Gymnocypris eckloni
RAN Fengxia1, JIN Wenjie1, DUANZHI Zhuoma1, HUANG Shen1, LIU Yanhui1, LI Zixuan1, WANG Zhenji2, WU Minghui1, JIAN Shenglong2, WANG Guojie2, LI Changzhong1*
1.College of Eco-Environmental Engineering, Qinghai University, Xining 810016, China； 2.Qinghai Fishery Environment Monitoring Station, Xining 810012, China
Abstract: To evaluate the influence of Zn2+ on eckloni naked carp Gymnocypriseckloni and screen the effective biomarkers, juvenile eckloni naked carp with body mass of (10±3) g was exposed to Zn2+prepared by ZnSO4·7H2O at concentration of 1, 2, 5, 10 and 20 mg/L for determination of the LD50 of Zn2+, and the expression of nuclear factor E2 related factor 2 (Nrf2), and genes of copper zinc superoxide dismutase (Cu/Zn-SOD), manganese superoxide dismutase (Mn-SOD), catalase (CAT) and glutathione peroxidase (GPx) in gill, kidney and liver tissues were detected by qPCR, the response levels of each gene heat map was analyzed in the three tissues by heat map, and change in the enzyme activities of SOD, CAT and GPx were measured by absorbance method. It was found that the median lethal dose (LD50) of Zn2+ was 5.0 mg/L in 24 h, 3.2 mg/L in 48 h, 2.5 mg/L in 72 h and 2.0 mg/L in 96 h with safe concentration of 0.2 mg/L. The mRNA expression levels of Nrf2, Cu/Zn-SOD, Mn-SOD, CAT and GPx and the activities of SOD, CAT and GPx were shown to be increased in gill, kidney and liver of eckloni naked carp within 96 h of Zn2+ stress, with the different extent of increase. The heatmap analysis of gene expression showed that there was lower relative expression of Nrf2 than that in four downstream genes in the three tissues, especially in kidney and liver tissues. The findings indicated that the gene expression levels of Nrf2, Cu/Zn-SOD, Mn-SOD, CAT and GPx and the activities of related enzymes were correlated with the time of Zn2+ stress and tissue specificity, and thus were used as potential biomarkers for early warning of water Zn2+ pollution.
2021, Vol. 36 
