Lazado Carlo C, Voldvik Vibeke, Breiland Mette W, Osório João, Hansen Marianne H S, Krasnov Aleksei
Nofima, The Norwegian Institute of Food, Fisheries and Aquaculture Research, 1433 Ås, Norway.
Nofima, The Norwegian Institute of Food, Fisheries and Aquaculture Research, 9019 Tromsø, Norway.
Antioxidants (Basel). 2020 Nov 18;9(11):1144. doi: 10.3390/antiox9111144.
The olfactory organs of fish have vital functions for chemosensory and defence. Though there have been some ground-breaking discoveries of their involvement in immunity against pathogens in recent years, little is known about how they respond to non-infectious agents, such as exogenous oxidants, which fish encounter regularly. To this end, we employed Atlantic salmon () as a model to study the molecular responses at the nasal olfactory mucosa of a teleost fish when challenged with oxidants. Microarray analysis was employed to unravel the transcriptional changes at the nasal olfactory mucosa following two types of in vivo exposure to peracetic acid (PAA), a highly potent oxidative agent commonly used in aquaculture: Trial 1: periodic and low dose (1 ppm, every 3 days over 45 days) to simulate a routine disinfection; and Trial 2: less frequent and high dose (10 ppm for 30 min, every 15 days, 3 times) to mimic a bath treatment. Furthermore, leukocytes from the olfactory organ were isolated and exposed to PAA, as well as to hydrogen peroxide (HO) and acetic acid (AA)-the two other components of PAA trade products-to perform targeted cellular and molecular response profiling. In the first trial, microarrays identified 32 differentially expressed genes (DEG) after a 45-day oxidant exposure. Erythrocyte-specific genes were overly represented and substantially upregulated following exogenous oxidant exposure. In Trial 2, in which a higher dose was administered, 62 DEGs were identified, over 80% of which were significantly upregulated after exposure. Genes involved in immune response, redox balance and stress, maintenance of cellular integrity and extracellular matrix were markedly affected by the oxidant. All chemical stimuli (i.e., PAA, HO, AA) significantly affected the proliferation of nasal leukocytes, with indications of recovery observed in PAA- and HO-exposed cells. The migration of nasal leukocytes was promoted by HO, but not much by PAA and AA. The three chemical oxidative stressors triggered oxidative stress in nasal leukocytes as indicated by an increase in the intracellular reactive oxygen species level. This resulted in the mobilisation of antioxidant defences in the nasal leukocytes as shown by the upregulation of crucial genes for this response network. Though qPCR revealed changes in the expression of selected cytokines and heat shock protein genes following in vitro challenge, the responses were stochastic. The results from the study advance our understanding of the role that the nasal olfactory mucosa plays in host defence, particularly towards oxidative chemical stressors.
鱼类的嗅觉器官对于化学感应和防御具有至关重要的功能。尽管近年来在其参与针对病原体的免疫方面有一些开创性的发现，但对于它们如何应对非传染性因子，如鱼类经常遇到的外源性氧化剂，却知之甚少。为此，我们以大西洋鲑鱼（ ）为模型，研究硬骨鱼鼻腔嗅觉黏膜在受到氧化剂挑战时的分子反应。采用微阵列分析来揭示在两种体内暴露于过氧乙酸（PAA）（一种水产养殖中常用的高效氧化剂）后鼻腔嗅觉黏膜的转录变化：试验1：定期低剂量（1 ppm，在45天内每3天一次）以模拟常规消毒；试验2：不频繁高剂量（10 ppm，30分钟，每15天一次，共3次）以模拟浸浴处理。此外，从嗅觉器官分离白细胞，并使其暴露于PAA以及过氧化氢（HO）和乙酸（AA）（PAA商品的另外两种成分），以进行靶向细胞和分子反应谱分析。在第一次试验中，微阵列在45天氧化剂暴露后鉴定出32个差异表达基因（DEG）。外源性氧化剂暴露后，红细胞特异性基因过度表达且显著上调。在试验2中，给予更高剂量，鉴定出62个DEG，其中超过80%在暴露后显著上调。参与免疫反应、氧化还原平衡和应激、细胞完整性维持和细胞外基质的基因受到氧化剂的显著影响。所有化学刺激（即PAA、HO、AA）均显著影响鼻腔白细胞的增殖，在暴露于PAA和HO的细胞中观察到恢复迹象。HO促进鼻腔白细胞的迁移，但PAA和AA的促进作用不大。如细胞内活性氧水平升高所示，这三种化学氧化应激源在鼻腔白细胞中引发了氧化应激。这导致鼻腔白细胞中抗氧化防御机制的动员，如该反应网络关键基因的上调所示。尽管qPCR显示在体外刺激后选定细胞因子和热休克蛋白基因的表达发生了变化，但反应是随机的。该研究结果推进了我们对鼻腔嗅觉黏膜在宿主防御中，特别是对氧化化学应激源所起作用的理解。
