为了评估养殖条件下青鱼(Mylopharygodon piceus)不同组织的状态和分析青鱼不同肠段的功能分化,使用组织学半定量系统对青鱼的鳃、肝、脾和肠进行评估,并使用酶活检测分析青鱼不同肠段中消化酶和抗氧化酶的分布.结果 表明:青鱼的鳃、肝和脾的状况良好,处于Ⅰ级和Ⅱ级变化,肠道是最受影响的器官,达到Ⅲ级变化,在肠道的组织学分析中发现肠黏膜上皮细胞增生和固有层易碎和坏死.青鱼的Fulton状态指数(fulton's conditional factor,CF)介于1.01到2.30之间,均值为1.19;肝体指数(hepatic somatic index,HSI)介于0.29到0.93之间,均值为0.58,表明被检测的青鱼状态良好.在青鱼的肠道中,消化酶和抗氧化酶在不同肠段的分布存在显著差异,前肠淀粉酶、脂肪酶和胰蛋白酶的活性显著高于后肠,后肠中超氧化物歧化酶(superoxide dismutase,SOD)、谷胱甘肽还原酶(glutathione reductase,GR)、过氧化氢酶(catalase,CAT)活性和总抗氧化能力(total antioxidant capacity,T-AOC)显著高于前肠.结果 可以为养殖鱼类组织状态评估和肠道不同部分功能差异分析提供一定的参考资料.
为探究miR-462在嗜水气单胞菌感染草鱼肾脏细胞(Ctenopharyngodon idella kideny,CIK)后的调控机制,实验利用荧光定量技术检测了CIK细胞感染嗜水气单胞菌后miR-462表达水平的变化;运用RNAhybrid软件预测miR-462的靶基因,利用双荧光素酶报告基因系统进行确定;此外还分析了miR-462对靶基因下游基因的调控作用.结果 显示,在CIK细胞感染嗜水气单胞菌的过程中,miR-462的表达发生显著变化;cx32.2、slc9a3.1和tbk1的表达先降低后升高,与miR-462的表达模式呈负相关.双荧光素酶报告系统显示,miR-462可靶向cx32.2、slc9a3.1和tbk1的3′非编码区抑制其表达,过表达miR-462可以显著抑制cx32.2、slc9a3.1和tbk1的表达.转染miR-462模拟物后,下游slc4a4a、tnfrsf5、cxcl9和cxcl11基因的表达受到抑制.研究表明,miR-462参与调控嗜水气单胞菌感染后草鱼CIK细胞中的免疫应答.cx32.2、slc9a3.1和tbk1被鉴定为miR-462的靶基因.miR-462可通过靶向slc9a3.1和tbk1影响下游基因的功能.
Grass carp septicemia is a systemic inflammatory response that develops following a bacterial infection. The hyperinflammatory state develops could lead to septic shock and lethality. There is increasing evidence that microRNAs are involved in the regulation of the inflammatory response. In the present study, miR-21 was confirmed to be involved in the inflammatory response following infection with Aeromonas hydrophila and LPS stimulation. Both jnk and ccr7 were identified as target gene of miR-21 by overexpression, inhibition, and dual luciferase reporter assays experiments. Meanwhile, miR-21 targets the jnk and ccr7 to modulate downstream pro-inflammatory factors tnf-α, il-1β, il-6, and il-12. Our results provide a theoretical basis for exploring the molecular mechanism of grass carp miR-21 regulating inflammation.
