Background

Environmental hypoxia affects the survival and development of organisms. It is also an important environmental factor that leads to oxidative damage. Hypoxia is a condition in which tissues are deprived of oxygen; reoxygenation is the phenomenon in which hypoxic tissues are exposed to oxygen. Hypoxia-reoxygenation is vital in pathogenesis, where the production of reactive oxygen species and antioxidant disparity significantly contribute to disease progression, and it is one of the most common physiological stressors in the aquaculture industry.

Methods and results

In this study, the full length of complementary DNA (cDNA) of the manganese superoxide dismutase (Mn-SOD) gene of healthy cobia Rachycentron canadum was analysed using rapid amplification of cDNA ends. The real-time quantitative Polymerase Chain Reaction was used to measure the expression levels of Mn-SOD mRNAs in various tissues (heart, muscle, brain, liver, kidney, gill, intestine, and spleen). The 2^–ΔΔCT method was used to performed the expression analysis. The experimental data were analysed using SPSS ver. 19.0 (https://spss.software.informer.com/19.0/). P < 0.05 and P < 0.01 were set as significant differences. The values were articulated as mean ± standard deviation. The Mn-SOD gene cDNA sequence was 1209 bp long, including a 684 bp open reading frame, 42 bp 5'UTR and 483 bp 3'UTR, encoding 227 amino acids. Under hypoxia-reoxygen stress, the expression of Mn-SOD in brain tissue was significantly lower than in the control group after 8 h of reoxygenation and higher than the control group after 24 h. Hypoxia and subsequent reoxygenation triggered a disturbance in antioxidant homeostasis, displayed in the modification of GPx expression/activity in the liver: GPx was improved.

Conclusions

These results provide valuable information on the role of Mn-SOD regulation in oxidative stress caused by hypoxia.

中文翻译：

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军曹鱼缺氧胁迫下Mn-SOD基因的克隆及其mRNA表达差异及抗氧化酶活性

背景

环境缺氧影响生物体的生存和发育。它也是导致氧化损伤的重要环境因素。缺氧是组织缺氧的一种情况。复氧是缺氧组织暴露于氧气的现象。缺氧复氧在发病机制中至关重要，其中活性氧的产生和抗氧化差异显着促进疾病进展，是水产养殖业中最常见的生理应激源之一。

方法和结果

在这项研究中，使用 cDNA 末端的快速扩增分析了健康军曹鱼Rachycentron canadum的锰超氧化物歧化酶 (Mn-SOD) 基因的全长互补 DNA (cDNA) 。实时定量聚合酶链反应用于测量不同组织（心脏、肌肉、脑、肝、肾、鳃、肠和脾）中 Mn-SOD mRNA 的表达水平。2 ^-ΔΔCT方法用于进行表达分析。实验数据使用 SPSS ver. 进行分析。19.0 (https://spss.software.informer.com/19.0/)。P  < 0.05 和P < 0.01 被设置为显着差异。这些值被表述为平均值±标准偏差。Mn-SOD基因cDNA序列长1209 bp，包括一个684 bp的开放阅读框，42 bp 5'UTR和483 bp 3'UTR，编码227个氨基酸。在缺氧-复氧应激下，复氧8 h后脑组织中Mn-SOD的表达明显低于对照组，24 h后高于对照组。缺氧和随后的复氧引发了抗氧化稳态的紊乱，表现为肝脏中 GPx 表达/活性的改变：GPx 得到了改善。

结论

这些结果为 Mn-SOD 调节在缺氧引起的氧化应激中的作用提供了有价值的信息。