急性非洲猪瘟脑损伤及NF-κB介导脑水肿形成机制研究

doi:10.16431/j.cnki.1671-7236.2022.03.027

摘要/Abstract

摘要： 【目的】在试验条件下研究非洲猪瘟病毒（African swine fever virus，ASFV）所致急性脑损伤及核因子κB （NF-κB）介导脑水肿发生的相关病理机制。【方法】 18头健康长白猪随机分为2组，攻毒组（13头）和对照组（5头），攻毒组肌内注射剂量为10²HAD₅₀/mL （HAD₅₀：半数红细胞吸附量）的ASFV毒株Pig/HLJ/18，对照组注射等体积生理盐水，试验期为15 d。试验期间观察临床症状，剖检死亡猪并观察脑部病变；利用原位PCR检测进行病毒定位；HE染色及甲苯胺蓝染色观察脑组织病理变化；免疫组化染色法检测脑组织中肿瘤坏死因子-α（TNF-α）、白介素-1β（IL-1β）、干扰素-γ（IFN-γ）、NF-κB、基质金属蛋白酶9（MMP-9）、水通道蛋白4（AQP-4）的表达。【结果】攻毒组9头猪表现出临床神经症状，脑部剖检病变主要为脑膜充血和不同程度的脑实质水肿；ASFV主要位于脑部微血管中；病变早期主要为脑水肿，脑皮质区结构疏松、血管周围间隙增宽、神经元肿胀变圆、染色变淡，中后期除了表现脑水肿的特征外，还可见脑血管充血、多量微血栓形成及淋巴细胞浸润；免疫组化结果显示，攻毒组TNF-α、IL-1β、IFN-γ、NF-κB及MMP-9主要在神经元及胶质细胞中表达，AQP-4的阳性细胞主要是微血管周围的星形胶质细胞，与对照组相比，攻毒组上述6种因子的阳性表达率均极显著增高（P<0.01）。【结论】急性非洲猪瘟脑损伤的主要表现为脑膜血管充血出血和脑实质水肿、组织学病变显示病毒性脑炎，ASFV感染脑部，促进炎性因子的异常高表达，通过激活NF-κB信号通路对TNF-α、IL-1β、IFN-γ的转录进行调控，使这几种炎性因子的产生和释放增多，扩大炎症反应，影响血脑屏障的通透性，还能上调MMP-9与AQP-4的表达，破坏血脑屏障，促进脑水肿的发生发展。

关键词: 非洲猪瘟; 脑水肿; 炎性因子; 核因子κB

Abstract: 【Objective】 The experiment was aimed to study the acute brain injury caused by African swine fever virus (ASFV) and the related pathological mechanisms of NF-κB mediated brain edema under experimental conditions.【Method】 Eighteen healthy Landrace pigs were randomly divided into two groups:Challenge group (n=13) and control group (n=5).The challenge group was injected intramuscularly with the ASFV strain Pig/HLJ/18 with a dose of 10² HAD₅₀/mL (HAD₅₀:half of the red blood cell adsorption), the control group was injected with the same volume of normal saline, and the experiment lasted for 15 days.During the experiment, the clinical symptoms were observed, the dead pigs were dissected and the brain lesions were observed.Virus localization was performed by in situ PCR, HE staining and toluidine blue staining were used to observe the histological changes of brain.Immunohistochemical staining was used to detect the expression of TNF-α, IL-1β, IFN-γ, NF-κB, MMP-9, and AQP-4 in brain tissue.【Result】 9 pigs in the challenge group showed clinical neurological symptoms, and the main brain lesions were meningeal congestion and different degrees of brain parenchymal edema.ASFV was mainly located in cerebral microvessels.The early stage of the lesion was mainly cerebral edema, loose structure of cerebral cortex, widening of perivascular space, swelling and rounding of neurons and light staining.In the middle and late stage, in addition to the characteristics of cerebral edema, cerebral vascular congestion, a large amount of micro thrombosis and lymphocyte infiltration were also seen.Immunohistochemical results showed that TNF-α, IL-1β, IFN-γ, NF-κB, and MMP-9 were mainly expressed in neurons and glial cells in the challenge group, and the positive cells of AQP-4 were mainly astrocytes around capillaries.Compared with the control group, the positive expression rates of the above 6 factors in the challenge group were extremely significantly higher (P<0.01).【Conclusion】 In summary, the main manifestations of acute African swine fever brain injury were meningeal vascular congestion, hemorrhage and brain parenchymal edema, and histological lesions showed viral encephalitis.ASFV infected the brain and promoted abnormally high expression of inflammatory factors.By activating the NF-κB signaling pathway, it regulated the transcription of TNF-α, IL-1β and IFN-γ, which increased the production and release of these inflammatory factors, expanded the inflammatory response, and affected the permeability of the blood-brain barrier.It could also up-regulate the expression of MMP-9 and AQP-4, destroy the blood-brain barrier, and promote the occurrence and development of cerebral edema.

Key words: African swine fever; brain edema; inflammatory factor; NF-κB

中图分类号:

S852.65⁺1

罗颖, 张先东, 李慧, 李樵锋, 刘伟琪, 付静静, 黄璐琦, 邓桦, 杨鸿. 急性非洲猪瘟脑损伤及NF-κB介导脑水肿形成机制研究[J]. 中国畜牧兽医, 2022, 49(3): 1048-1056.

LUO Ying, ZHANG Xiandong, LI Hui, LI Qiaofeng, LIU Weiqi, FU Jingjing, HUANG Luqi, DENG Hua, YANG Hong. Study on Acute African Swine Fever Brain Injury and NF-κB Mediated Brain Edema Formation Mechanism[J]. China Animal Husbandry and Veterinary Medicine, 2022, 49(3): 1048-1056.

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