摘要
为研究鸭Toll-like receptor 4(TLR4)在多杀性巴氏杆菌(Pm)感染樱桃谷鸭致肝损伤机制中作用,本研究首先采用荧光定量PCR方法检测6羽健康组30日龄樱桃谷鸭的TLR4基因在不同组织中的转录水平,结果显示,TLR4在健康樱桃谷鸭各组织中均有转录,但在肝脏中的转录水平较高,因此本研究选取肝脏进行Pm感染樱桃谷鸭致病机制研究。本研究将72羽30日龄樱桃谷鸭随机分为对照组和感染组,感染组每羽脚蹼注射浓度为500 cfu/mL的Pm菌液0.6 mL,观察感染鸭的临床症状,于感染后不同时间剖解感染鸭并观察肝脏的剖检病变,结果可见感染组樱桃谷鸭出现精神萎靡、食欲不振、口鼻眼有分泌物等症状,肝脏布满针尖大小白色的病灶;将肝组织制备病理切片并观察病理学变化,观察可见感染鸭肝组织出现明显的变性坏死。进一步采用荧光定量PCR方法检测感染鸭肝组织内TLR4介导的MyD88依赖途径信号通路中相关因子的转录水平,结果显示,其肝组织内TLR4、IL-6转录水平与对照组相比在感染后36 h显著上调(p<0.05),MyD88、TNF-α与对照组相比在感染后36 h极显著上调(p<0.01),NF-кB与对照组相比在感染后24 h极显著上调(p<0.01)。本研究首次证实Pm能激活樱桃谷鸭肝脏内TLR4介导的MyD88依赖途径的信号通路,进一步启动下游的炎症因子参与了鸭霍乱的肝损伤过程,为进一步研究Pm对樱桃谷鸭的致病机制提供参考依据。
To investigate the mechanism of liver injury induced by duck Toll-likereceptor4(TLR4)in cherry valley ducks infected with Pasteurella multocida(P.multocida),the transcription levels of TLR4 gene in different tissues of 6 healthy 30-dayold cherry valley ducks was detected by fluorescence quantitative PCR.The results showed that TLR4 was transcribed in various tissues of healthy cherry valley ducks,but at a higher level in the liver.Therefore,in this study,the liver was selected to study the pathogenic mechanism of cherry valley duck infected with P.multocida.In this study,7230-day-old cherry valley ducks were randomly divided into control group and infection group.In the infected group,0.6 m L of P.multocida bacterial solution with a concentration of 500 cfu/m L was injected into the flipper of each infected group.The clinical symptoms of infected ducks were observed.The infected ducks were dissected at different time after infection and the pathological changes of liver were observed.The results showed that the cherry valley ducks in the infected group had symptoms such as apathy,loss of appetite,and mouth,nose and eye secretions,and the liver was covered with white lesions of needle tip size.At the same time,the liver tissues were prepared for pathological sections and the pathological changes were observed,and the liver tissues of infected ducks showed significant degeneration and necrosis.Furthermore,the transcription levels of related factors in TLR4-mediated My D88-dependent pathway signaling pathway in infected duck liver tissues were detected by fluorescence quantitative PCR.The results showed that the transcription levels of TLR4 and IL-6 in their liver tissues were significantly up-regulated at 36 h after infection compared with the control group(p<0.05),My D88 and TNF-αwere extremely significantly up-regulated at 36 h after infection compared with the control group(p<0.01),and NF-κB was extremely significantly up-regulated at 24 h after infection compared with the control group(p<0.01).This study confirmed for the first time that P.multocida can activate TLR4-mediated My D88-dependent pathway signaling pathway in the liver of cherry valley ducks,further initiating downstream inflammatory factors involved in the process of liver injury in duck cholera,which provides a theoretical basis for further study of the pathogenic mechanism of P.multocida on cherry valley duck.
作者
周静静
王凯
程国富
胡薛英
张万坡
谷长勤
ZHOU Jing-jing;WANG Kai;CHENG Guo-fu;HU Xue-ying;ZHANG Wan-po;GU Chang-qin(College of Veterinary Medicine,Huazhong Agricultural University,Wuhan 430070,China)
出处
《中国预防兽医学报》
CAS
CSCD
北大核心
2021年第11期1197-1201,1233,共6页
Chinese Journal of Preventive Veterinary Medicine
基金
国家重点研发计划(2016YFD0500407)
