Nitrite is a major environmental pollutant in aquatic environments that negatively affects aquatic species. In this study, we investigated the impact of nitrite exposure on plasma biochemical parameters and immune responses in Takifugu rubripes. Fish were exposed to various concentrations of nitrite (0, 0.5, 1, 3, and 6 mM) for 96 h. After 0, 12, 24, 48, and 96 h of exposure, fish blood samples were collected to assay the levels of total protein (TP), albumin (Alb), glutamic-oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase (ALT), complement C3 (C3), complement C4 (C4), immunoglobulin (IgM), and lysozyme activity (LZM). The gills were sampled to analyze the mRNA levels of heat shock protein 70 (hsp70), heat shock protein 90 (hsp90), tumor necrosis factor α (tnf-α), B-cell activating factor (baff), interleukin-6 (il-6), and interleukin-12 (il-12). Levels of GOT, ALT, C3, and C4 were significantly enhanced in the high nitrite concentration group (3 and 6 mM), whereas those of TP, Alb, LZM, and IgM decreased significantly with the same treatments. Nitrite significantly upregulated hsp70, hsp90, tnf-α, il-6, il-12, and baff mRNA levels after 96 h of exposure. These results indicated that nitrite exposure altered the blood physiological status and immune system response, resulting in dysfunction and immunotoxicity in T. rubripes. Furthermore, our results reveal the possible mechanism of aquatic-nitrite-induced toxicity in fish.

中文翻译：

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亚硝酸盐暴露对T柳中血浆生化参数和免疫相关反应的影响。

亚硝酸盐是水生环境中的主要环境污染物，会对水生物种产生负面影响。在这项研究中，我们调查了亚硝酸盐暴露对T柳中血浆生化参数和免疫反应的影响。将鱼暴露于各种浓度的亚硝酸盐（0、0.5、1、3和6 mM）中96小时。暴露0、12、24、48和96小时后，收集鱼血样本以检测总蛋白（TP），白蛋白（Alb），谷氨酸-草酰乙酸转氨酶（GOT），谷氨酸-丙酮酸转氨酶（ALT）的水平），补体C3（C3），补体C4（C4），免疫球蛋白（IgM）和溶菌酶活性（LZM）。对g进行采样以分析热休克蛋白70（hsp70），热休克蛋白90（hsp90），肿瘤坏死因子α（tnf-α），B细胞激活因子（baff），白介素6（il -6），和白介素12（il-12）。在高亚硝酸盐浓度组（3和6 mM）中，GOT，ALT，C3和C4的水平显着提高，而在相同的处理下，TP，Alb，LZM和IgM的水平显着降低。在暴露96小时后，亚硝酸盐显着上调了hsp70，hsp90，tnf-α，il-6，il-12和baff mRNA的水平。这些结果表明，亚硝酸盐的暴露改变了血液的生理状态和免疫系统反应，从而导致了红三叶草的功能障碍和免疫毒性。此外，我们的结果揭示了水生亚硝酸盐诱导的鱼类毒性的可能机制。在暴露96小时后，亚硝酸盐显着上调了hsp70，hsp90，tnf-α，il-6，il-12和baff mRNA的水平。这些结果表明，亚硝酸盐的暴露改变了血液的生理状态和免疫系统反应，从而导致了红三叶草的功能障碍和免疫毒性。此外，我们的结果揭示了水生亚硝酸盐诱导的鱼类毒性的可能机制。在暴露96小时后，亚硝酸盐显着上调了hsp70，hsp90，tnf-α，il-6，il-12和baff mRNA的水平。这些结果表明，亚硝酸盐的暴露改变了血液的生理状态和免疫系统反应，从而导致了红三叶草的功能障碍和免疫毒性。此外，我们的结果揭示了水生亚硝酸盐诱导的鱼类毒性的可能机制。