Liu Jia, Zhang Faye, Yan Zihao, Guo Zhengyao, Lu Yuqian, Yao Baolan, Li Yuehong, Lv Wenfa
College of Animal Science and Technology/College of Animal Medicine, Jilin Agricultural University, Changchun 130118, China; Ministry of Education Laboratory of Animal Production and Quality Security, Jilin Agricultural University, Changchun 130118, China.
Georgia Institute of Technology, Atlanta, USA.
Ecotoxicol Environ Saf. 2025 Jan 15;290:117571. doi: 10.1016/j.ecoenv.2024.117571. Epub 2024 Dec 20.
This study investigated the effects of long-term NaHCO stress on serum immunity, antioxidant capacity, intestinal tight junction, intestinal microbiota, mitochondrial function and autophagy in crucian carp. A total of 240 fish (31.19 ± 1.03 g) were randomly allocated to two groups and treated with 0 mmol/L (CK) and 50 mmol/L NaHCO (CA) respectively, to simulate the carbonate alkaline water environment. All of the experimental fish were cultured for 8 weeks. The results showed that compared to the control group, NaHCO stress significantly decreased the levels of the serum immunity indices (AKP, ACP, C3, C4, IgM, LZM) and the antioxidant capacity indices (CAT, GSH-PX, SOD, T-AOC), while markedly increasing the content of MDA. Additionally, NaHCO influenced the mRNA expression of HSP90, Nrf2, Keap1, and HO-1. Compared to the control group, the levels of ZO-1, Claudin-2, Occludin-a, and Occludin-b mRNA significantly decreased in the NaHCO stress group. The levels of ATG5, ATG7, and Beclin1 mRNA and protein were significantly increased along with the levels of LC3b mRNA and the ratio of protein LC3 II /LC3 I. Compared to the control group, intestinal mitochondria in the NaHCO stress group were visibly swollen and largely broken, with reductions in ridges and a large proportion of the area dissolved in the matrix. The mitochondrial membrane potential and the activities of ATPase were significantly decreased, leading to mitochondria dysfunction. In addition, 3147 differentially expressed genes were identified from transcriptome sequencing, among which several genes related to mitochondria and autophagy were significantly enriched. Compared to the control group, the NaHCO stress decreased the ACE index and increased the abundance of Proteobacteria while decreased the abundance of Actinobacteria and Firmicutes. In conclusion, NaHCO induced oxidative damage, microbiota alterations, mitochondria dysfunction, and autophagy in the intestines of crucian carp. The results of this study have characterized the molecular mechanisms of intestinal injury in crucian carp caused by NaHCO stress, and thus provide empirical support for aquaculture in saline-alkali waters.
本研究调查了长期碳酸氢钠（NaHCO）胁迫对鲫鱼血清免疫、抗氧化能力、肠道紧密连接、肠道微生物群、线粒体功能和自噬的影响。将总共240尾鱼（31.19±1.03克）随机分为两组，分别用0毫摩尔/升（CK）和50毫摩尔/升NaHCO（CA）处理，以模拟碳酸盐碱性水环境。所有实验鱼均养殖8周。结果表明，与对照组相比，NaHCO胁迫显著降低了血清免疫指标（碱性磷酸酶、酸性磷酸酶、补体C3、补体C4、免疫球蛋白M、溶菌酶）和抗氧化能力指标（过氧化氢酶、谷胱甘肽过氧化物酶、超氧化物歧化酶、总抗氧化能力）的水平，同时显著增加了丙二醛的含量。此外，NaHCO影响了热休克蛋白90、核因子E2相关因子2、 Kelch样环氧氯丙烷相关蛋白1和血红素加氧酶-1的mRNA表达。与对照组相比，NaHCO胁迫组中闭合蛋白-1、闭合蛋白-2、紧密连接蛋白-a和紧密连接蛋白-b的mRNA水平显著降低。自噬相关蛋白5、自噬相关蛋白7和Beclin1的mRNA和蛋白水平以及微管相关蛋白1轻链3β的mRNA水平和蛋白微管相关蛋白1轻链3Ⅱ/微管相关蛋白1轻链3Ⅰ的比例显著增加。与对照组相比，NaHCO胁迫组的肠道线粒体明显肿胀且大部分破裂，嵴减少，基质中有很大比例的区域溶解。线粒体膜电位和ATP酶活性显著降低，导致线粒体功能障碍。此外，通过转录组测序鉴定出3147个差异表达基因，其中几个与线粒体和自噬相关的基因显著富集。与对照组相比，NaHCO胁迫降低了放线菌-腔菌-拟杆菌（ACE）指数，增加了变形菌门的丰度，同时降低了放线菌门和厚壁菌门的丰度。总之，NaHCO诱导鲫鱼肠道氧化损伤、微生物群改变、线粒体功能障碍和自噬。本研究结果阐明了NaHCO胁迫导致鲫鱼肠道损伤的分子机制，从而为盐碱水域水产养殖提供了实证支持。
