低氧胁迫和恢复对杂交黄颡鱼“黄优1号”肠道组织的影响

HYPOXIA STRESS AND RECOVERY ON INTESTINAL TISSUE OF HYBRID YELLOW CATFISH “HUANGYOU-1” (PELTEOBAGRUS VACHELLI ♂ × PELTEOBAGRUS FULVIDRACO ♀)

  • 摘要: 为探究低氧胁迫和恢复对杂交黄颡鱼(Pelteobagrus fulvidraco) “黄优1号”肠道组织的影响, 研究运用酶活测定、HE染色、qRT-PCR、TUNEL检测及16S rRNA测序技术等方法, 分析低氧胁迫(1.0±0.1) mg/L和恢复下(7.0±0.5) mg/L该鱼肠道氧化应激指标、组织结构形态、细胞凋亡及微生物组成变化。结果显示: (1)在低氧胁迫下肠道中抗氧化酶活性(SOD、CAT、GSH-Px)、能量代谢酶活性(LDH)、丙二醛(MDA)和脂质过氧化物(LPO)含量显著升高, 恢复溶氧后氧化应激反应也比较剧烈。(2)低氧胁迫阶段, 肠道组织受损现象逐渐加剧, 杯状细胞肿胀、黏膜层被侵蚀, 恢复溶氧24h后, 缺氧引起的生理变化并未得到明显改善。(3)肠道组织细胞凋亡程度随着低氧时间的延长而加剧, 凋亡相关基因(bax、caspase9p53)的表达量显著升高, bcl-2基因的表达量则减少。(4)低氧胁迫阶段肠道微生物相对丰度降低, 低氧胁迫72h的处理组中以厚壁菌门(Firmicutes)(47.8%)和拟杆菌门(Bacteroidetes)(40.6%)的丰度最为优势, 恢复溶氧后肠道菌群数量有所增加; KEGG功能预测显示, 多数肠道微生物与代谢通路相关。研究结果可为解析低氧和恢复下杂交黄颡鱼“黄优1号”肠道组织内环境稳态调控机制提供理论依据。

     

    Abstract: At present, the research on environmental stress of fish intestinal tissues has attracted the attention of scholars. In order to explore the effects of hypoxia (1.0±0.1) mg/L and recovery (7.0±0.5) mg/L on the intestinal tissues of hybrid yellow catfish “Huangyou-1”, the changes of intestinal oxidative stress index, histological morphology, cell apoptosis and microbial composition were analyzed by enzyme activity determination and H & E staining, qRT-PCR, TUNEL detection and 16S rRNA sequencing technology. The results showed that: (1) Antioxidant enzyme activities (SOD, CAT, GSH-Px), energy metabolism enzyme activity (LDH), malondialdehyde (MDA) and lipid peroxide (LPO) of intestine increased significantly under hypoxia stress, and the oxidative stress reaction was also severe after the recovery of dissolved oxygen. (2) After hypoxia stress, the intestinal tissue damage gradually intensified, the goblet cells were swelled and the mucosal layer was eroded. The physiological changes caused by hypoxia were not significantly improved after 24h oxygen recovery. (3) The degree of intestinal cell apoptosis intensified with the prolongation of hypoxia, and the expression levels of apoptosis-related genes (bax, caspase9 and p53) increased significantly, while the mRNA expression levels of bcl-2 decreased. (4) The relative abundance of intestinal microbes were reduced in the hypoxic stress stage. Among 72h hypoxic stress, Firmicutes (47.8%) and Bacteroidetes (40.6%) had the most dominant abundances, and the number of intestinal flora increased after the recovery of dissolved oxygen, KEGG function prediction showed that most of the intestinal microbes were related to metabolic pathways. The research results can provide a theoretical basis for analyzing the physiological regulation mechanism of hybrid yellow catfish “Huangyou-1” in response to hypoxia stress and recovery.

     

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