盐度胁迫对大黄鱼肝脏氧化损伤的作用机制

Mechanism of salinity stress on oxidative damage in the liver of Larimichthys crocea

为探讨盐度胁迫对大黄鱼(Larimichthys crocea)氧化损伤的作用机制,实验设置3个盐度梯度(12、25、40,分别记为低盐组L组、对照组C组、高盐组H组),对大黄鱼进行盐度胁迫实验,在实验的第1天、第3天和第7天提取肝脏样本,结果显示,低盐组和高盐组相比对照组,大黄鱼丙二醛(MDA)与脂质过氧化物(LPO)含量在第1、3和7天时均显著增加(P<0.05);过氧化物歧化酶(SOD)活力第1天均显著高于对照组,随后下降至第7天均显著低于对照组(P<0.05);过氧化氢酶(CAT)活力第1、7天均显著低于对照组(P<0.05),第3天各组无显著差异(P>0.05);溶菌酶(LZM)活力变化与SOD类似;碱性磷酸酶(AKP)活力变化趋势较复杂。铜锌超氧化物歧化酶(Cu/Zn-SOD)、锰超氧化物歧化酶(Mn-SOD)、CAT、c型溶菌酶(c-type LZM)、g型溶菌酶(g-type LZM)和AKP基因表达水平与对应的酶活力呈正相关(P<0.05);NF-E2相关因子2(Nrf2)和核转录因子-κB(NF-κB)基因表达水平分别与抗氧化酶和非特异性免疫酶基因表达水平呈正相关(P<0.05)。综上所述,大黄鱼可以通过提高抗氧化能力和非特异性免疫能力来抵御盐度胁迫对机体的氧化损伤。

Large yellow croaker Larimichthys crocea is a main commercial marine fish,output is the highest among sea cage-cultured fishes in China.In order to explore the mechanism of salinity stress on oxidative damage of L.crocea,three salinity gradients(12,25,40,respectively recorded as L,C,H)were set up in the experiment.L.crocea was subjected to salinity stress experiment,and samples were taken on the 1st,3rd and 7th days of the experiment.The results showed that the contents of malondialdehyde(MDA)and lipid peroxide(LPO)in the liver of L.crocea increased significantly on the 1st,3rd and 7th days compared with that of the control(P<0.05).The activities of superoxide dismutase(SOD)were all significantly higher than the control on the 1st day,then decreased and were all significantly lower than the control on the 7th day(P<0.05).The catalase(CAT)of the liver were siginificantly lower than the control on the 1st and 7th days(P<0.05),and showed no significant difference among groups on the 3rd day(P<0.05).Lysozyme(LZM)activities generally showed a similar trend with SOD.The alkaline phosphatase(AKP)activities showed a complex changing trend.The gene expression levels of copper zinc superoxide dismutase(Cu/Zn-SOD),manganese superoxide dismutase(Mn-SOD),CAT,c-type LZM,g-type LZM and AKP were positively correlated with corresponding enzyme activities(P<0.05);NF-E2 related factor 2(Nrf2)and nuclear transcription factor-κB(NF-κB)gene expression levels were positively correlated with the expression levels of antioxidant enzyme genes and non-specific immune enzyme genes,respectively(P<0.05).In sum,L.crocea could enhance salinity stress tolerance by improving antioxidant capacity and non-specific immunity.