急性氨氮胁迫对翘嘴鳜幼鱼抗氧化酶活性及炎症反应相关基因表达的影响

对照组，分别于胁迫0、6、12、24、48和96 h后测定抗氧化酶活性及炎症反应相关基因的相对表达量。【结果】翘嘴鳜幼鱼的96 h-LC50为48.65 mg/L（非离子氨0.47 mg/L）。翘嘴鳜幼鱼在96 h的急性氨氮胁迫过程中，其肝脏超氧化物歧化酶（SOD）活性、过氧化氢酶（CAT）活性和谷胱甘肽（GSH）含量均呈先升高后降低的变化趋势;脂质过氧化物（LPO）在肝脏中的累积量随胁迫时间的延长逐渐增加，至胁迫96 h时达最高值（0.50 μmol/g），显著高于对照组（P<0.05，下同）。与对照组翘嘴鳜幼鱼相比，经氨氮胁迫后翘嘴鳜幼鱼肝脏IL-1β和IL-8基因的相对表达量均呈升高—降低—升高的变化趋势，于胁迫6 h起显著上调，分别于胁迫12和96 h时达最高值;TNF-α基因的相对表达量整体上呈先降低后升高的变化趋势，在胁迫6 h时显著低于对照组，但至胁迫96 h时其相对表达量达最高值;IL-1β、IL-8和TNF-α基因的相对表达量在胁迫96 h时均显著高于对照组;HSP90α基因的相对表达量呈先升高后降低的变化趋势，至胁迫96 h时，其相对表达量显著低于对照组。【结论】氨氮胁迫初期，翘嘴鳜幼鱼抗氧化系统被诱导激活，炎症反应相关基因表达上调;至胁迫后期，翘嘴鳜幼鱼抗氧化功能受抑制，而炎症反应相关基因表达持续上调。说明持续炎症反应及抗氧化系统功能受抑制是翘嘴鳜氨氮中毒死亡的主要原因。

关键词： 翘嘴鳜;氨氮胁迫;抗氧化酶;炎症反应相关基因;96 h半致死浓度（96 h-LC50）

中图分类号： S965.127                             文献标志码： A 文章编号：2095-1191（2019）08-1860-09

Effects of acute ammonia nitrogen stress on antioxidant enzymes activity and gene expression involved in inflammation

of juvenile Siniperca chuatsi

LIU Yu1， DING Wei-dong2， CAO Zhe-ming2， BING Xu-wen2*， XU Chang1，2，

YANG Fan1，2， ZHANG Chen-guang1，2， GU Xin-chi1， SUN A-jun2

（1Wuxi Fisheries College，Nanjing Agricultural University，Wuxi， Jiangsu  214081，China; 2Fisheries Research Center，Chinese Academy of Fishery Sciences，Wuxi， Jiangsu  214081， China）

Abstract：【Objective】In this study， antioxidant enzyme activity and expression level of genes involved in inflammation were studied to reveal the toxicity mechanism of juvenile Siniperca chuatsi under ammonia nitrogen stress to provide scientific basis for healthy breeding and water quality control management. 【Method】Undamaged juvenile S. chuatsi similar to each other in size were selected for 96 h acute ammonia nitrogen stress experiments. Using the obtained half lethal concentration（LC50） of ammonia-nitrogen in S. chuatsi as a basic concentration，the juvenile S. chuatsi were exposed to 48.65 mg/L concentration of ammonia nitrogen in water for 96 h. Fully aerated tap water（measured ammonia nitrogen value was 0.05 mg/L） was as control group. The activity of antioxidant enzymes and the expression of genes involved in inflammation were measured at 0， 6， 12， 24， 48  and 96 h respectively after stress. 【Result】The 96 h-LC50 of juvenile S. chuatsi was 48.65 mg/L（nonionic ammonia 0.47 mg/L）. In this study， the superoxide dismutase（SOD） activity， catalase （CAT） activity and glutathione（GSH） content in the liver of the experimental group have a tendency of increasing first and then decreasing. The accumulation of lipid peroxide（LPO） in liver increased gradually with the prolongation of stress time， and reached the maximum value at 96 h（0.50 μmol/g）， which was significantly higher than the control group（P<0.05， the same below）. Compared with control group， the relative expression of IL-1β and IL-8 genes in the liver of juvenile S. chuatsi presented up-down-up trend after ammonia nitrogen stress， and was significantly increased after 6 h stress， and peaked at 12 and 96 h after stress. The relative expression of TNF-α gene presented down-up trend as a whole， and was significantly lower than control after 6 h of stress， and reached the peak at 96 h. At 96 h of stress effect， the relative expressions of IL-1β and IL-8， TNF-α genes were all significantly higher than that of the control group. There was a tendency of increasing first then decreasing in the relative expression of HSP90α gene. After 96 h of stress effect， the relative expression of HSP90α gene was significantly lower than that of the control group. 【Conclusion】In the early stage of stress， the antioxidant system of juvenile S. chuatsi is induced to activation and the relative expression of inflammation-related genes up-regulates. However， in the late stage of stress， antioxidant function is inhibited and the relative expression of inflammation-related genes continue up-regulating. It is suggested that continuous inflammatory reaction and inhibition of antioxidant system may lead to the death of S. chuatsi exposed to ammonia nitrogen.

推荐访问： 幼鱼 胁迫 炎症 活性 抗氧化

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