Liu Bo, Gao Qiang, Liu Bo, Song Changyou, Sun Cunxin, Liu Mingyang, Liu Xin, Liu Yunke, Li Zhengzhong, Zhou Qunlan, Zhu Hao
Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, China.
Key Laboratory of Aquatic Animal Nutrition and Health, Freshwater Fisheries Research Center, Chinese Academy of Fishery Science, Wuxi 214081, China.
Antioxidants (Basel). 2022 Feb 22;11(3):440. doi: 10.3390/antiox11030440.
Salinity is one of the important environmental factors affecting survival and growth of aquatic animals. However, the impact of low-salinity stress on post-larvae at different development stages remains elusive. Therefore, the aim of this study was to explore the underlying mechanisms of hypotonic stress at different development stages of post-larvae through transcriptome analysis and antioxidant parameters detection. The salinity of the control group was 15 psu (S15) and the hypotonic stress group was 6 psu (S6). Samples were collected at 7 days-post-hatch (dph), 14 dph and 21 dph larvae. The results showed that hypotonic stress caused oxidative damage in post-larvae evidenced by decreased glutathione peroxidase (GSH-Px); superoxide dismutase (SOD); anti-superoxide anion free radical (ASAFR); and increased malondialdehyde (MDA); nitric oxide (NO); and inducible nitric oxide synthase (iNOS) levels. Transcriptome analysis showed that there were 1428, 1187, 132 DEGs including 301, 366, 4 up-regulated genes and 1127, 821, 128 down-regulated genes at 7 dph, 14 dph and 21 dph larvae under hypotonic stress, respectively. Furthermore, GO and KEGG enrichment indicated that hypotonic stress led to dysregulation of immune signals including lysosome and autophagy in the 7 dph larvae. The autophagy-related genes including beclin 1-associated autophagy-related key regulator (); ubiquitin-like modifier-activating enzyme ATG7 (); ; autophagy-related protein 13 (); nuclear receptor-binding factor 2 (); ubiquitin-like-conjugating enzyme ATG3 (); vacuole membrane protein 1 (); and autophagy-related protein 2 () decreased at 7 dph, and 14 dph larvae, and then increased at 21 dph larvae under hypotonic stress. In the 14 dph and 21 dph larvae, the renin-angiotensin system was activated. In conclusion, our data indicated that hypotonic stress reduced the antioxidant capacity and impaired the immune system in post-larvae, but as development progresses, the adaptability of post-larvae to hypotonic stress gradually increased, and might reach a new homeostasis through the RAS signaling pathway.
盐度是影响水生动物生存和生长的重要环境因素之一。然而，低盐度胁迫对不同发育阶段仔鱼的影响仍不清楚。因此，本研究旨在通过转录组分析和抗氧化参数检测，探索仔鱼不同发育阶段低渗胁迫的潜在机制。对照组盐度为15 psu（S15），低渗胁迫组盐度为6 psu（S6）。在孵化后7天（dph）、14 dph和21 dph的仔鱼中采集样本。结果表明，低渗胁迫导致仔鱼氧化损伤，表现为谷胱甘肽过氧化物酶（GSH-Px）、超氧化物歧化酶（SOD）、抗超氧阴离子自由基（ASAFR）水平降低，丙二醛（MDA）、一氧化氮（NO）和诱导型一氧化氮合酶（iNOS）水平升高。转录组分析表明，在低渗胁迫下，7 dph、14 dph和21 dph的仔鱼分别有1428、1187、132个差异表达基因（DEGs），其中上调基因分别为301、366、4个，下调基因分别为1127、821、128个。此外，基因本体（GO）和京都基因与基因组百科全书（KEGG）富集分析表明，低渗胁迫导致7 dph仔鱼的免疫信号失调，包括溶酶体和自噬。在低渗胁迫下，7 dph和14 dph的仔鱼中，自噬相关基因包括与beclin 1相关的自噬相关关键调节因子、泛素样修饰激活酶ATG7、自噬相关蛋白13、核受体结合因子2、泛素样结合酶ATG3、液泡膜蛋白1和自噬相关蛋白2表达下降，而在21 dph的仔鱼中则升高。在14 dph和21 dph的仔鱼中，肾素-血管紧张素系统被激活。总之，我们的数据表明，低渗胁迫降低了仔鱼的抗氧化能力并损害了其免疫系统，但随着发育的进行，仔鱼对低渗胁迫的适应性逐渐增强，并可能通过肾素-血管紧张素系统（RAS）信号通路达到新的稳态。
