斑马鱼肿瘤坏死因子(tnfα)及其受体(tnfrsf1a)应答细菌和病毒感染的表达

Expression analysis of zebrafish tumor necrosis factor (tnfα) and its receptor (tnfrsf1a) in response to bacterial and viral infections

摘要:

肿瘤坏死因子（tumor necrosis factor，Tnf）作为重要的炎症因子，在抵抗细菌和病毒感染以及清除被感染的细胞等方面发挥着重要的作用。对斑马鱼进行腹腔注射免疫刺激物、细菌和病毒病原，并采用荧光定量PCR技术分析tnfα及其受体[tnf receptor superfamily（tnfrsf） member 1a]在肾脏和脾脏中的表达。实验结果显示：tnfα和tnfrsf1a在斑马鱼各组织中均有常量表达。脂多糖（lipopolysaccharide，LPS）和聚肌苷酸-聚胞苷酸[polyinosinic acid-polycytidylic acid，poly（I：C）]能够调控肾脏和脾脏中tnfα和tnfrsf1a的表达。腹腔注射嗜水气单胞菌（Aeromonas hydrophila）感染斑马鱼后，tnfα在脾脏（48 h和72 h）和肾脏（72 h）中表达显著升高；tnfrsf1a在脾脏（48 h）表达水平也有显著上调。在注射迟缓爱德华氏菌（Edwardasiella tarda）的斑马鱼中，肾脏的tnfα表达显著增加，但在脾脏的表达则完全被抑制；tnfrsf1a基因在脾脏和肾脏（6 h和72 h）有明显上调。鲤春病毒血症病毒（spring viraemia of carp virus，SVCV）感染斑马鱼后，tnfα和tnfrsf1a在感染早期表达量有显著升高；而且在感染1~7 d中，肾脏的tnfrsf1a始终维持高水平诱导表达。实验结果表明：tnfα和tnfrsf1a在鱼类抵抗细菌和病毒感染过程中发挥重要作用。

Abstract:

Tumor necrosis factor (tnf) is a pro-inflammatory factor and plays an important role in immune response to bacterial and viral infections and clearance of infected cells. In this study, zebrafish were intraperitoneally (i.p.) injected with immunostimulants, bacterial or viral pathogens, and the expression of tnfα and its receptor (tnf receptor superfamily (tnfrsf) member 1 a) was analyzed by real-time PCR in kidney and spleen. The results showed that tnfα and tnfrsf1a were constitutively expressed in all the tissues analyzed. Lipopolysaccharide (LPS) and polyinosinic acid-polycytidylic acid (poly(I:C)) modulated the expression of tnfα and tnfrsf1a. Intraperitoneal injection of Aeromonas hydrophila led to significant increases of tnfα expression in spleen (at 48 h and 72 h) and kidney (at 72 h) and that of tnfrsf1a in spleen (at 48 h). In contrast, in fish i.p. injected with Edwardasiella tarda, the tnfα expression increased significantly at all the time points whilst totally inhibited in spleen. Increase of tnfrsf1a expression was also seen in both tissues at 6 h and 72 h. The expression levels of tnfα and tnfrsf1a were significantly elevated at the early stage of infection with SVCV, with that of tnfrsf1a detected significantly higher in kidney of infected fish than that in the control group throughout the infection period (1-7 d). The results indicate that tnfα and tnfrsf1a play important roles in immune defence against bacterial and viral infections.