H9N2亚型猪流感病毒诱导小鼠肺急性损伤模型的研究

Study on the Model of Acute Lung Injury Induced by Swine Influenza H9N2 in Mice

本试验采用100μLA/swine/HeBei/012/2008/(H9N2)猪流感病毒(H9N2SIV)经鼻腔接种6～8周龄的BALB/c小鼠,通过定时称量小鼠的采食量和体质量、观察肺病理组织学变化以及测量肺系数、肺湿质量/干质量、动脉血气和支气管肺泡灌洗液内炎性细胞等拟建立H9N2SIV感染诱导小鼠急性肺损伤模型。结果显示:(1)感染后第2天试验组小鼠出现精神沉郁、被毛松乱、采食量和体质量下降。感染后的第3天开始感染小鼠采食量和体质量显著下降(P<0.01);(2)试验组小鼠在感染后的第3天末出现死亡,死亡率约为62.5%,剖检可见肺部明显水肿、出血,肺泡内有大量的炎性细胞渗出;肺系数和湿质量/干质量比显著增加(P<0.01);(3)与对照组相比感染组小鼠动脉血中氧分压从第2天开始降低,第4天出现明显的差异(P<0.01),第6天最低时仅为(6.79±1.27)kPa,呈现严重的低氧血症,同时,二氧化碳分压显著上升;(4)支气管灌洗液(BALF)内炎性细胞在感染后第4-8天增加显著,尤其以肺泡巨噬细胞和多核型白细胞增加最为明显(P<0.01)。本研究证实采用A/swine/HeBei/012/2008/(H9N2)病毒感染小鼠引起肺组织弥漫性急性渗出性炎症为主的病理过程和严重的低氧血症,表明成功建立了H9N2SIV诱导小鼠的肺损伤模型,为进一步研究其对哺乳动物肺损伤的致病机理奠定基础。

Six to eight weeks old BALB/c mice were inoculated intranasally with A/swine/HeBei/012/2008/（H9N2）（100 μL） swine influenza virus diluted in sterile saline.The clinical signs and body loss were observed in group of eight infected mice,which was viewed as a measure of morbidity.Meanwhile,at the indicated time points after infection,lung histopathology,lung coefficient,lung wet weight/dry weight,arterial blood gas,inflammatory cells in bronchial alveolar lavage fluid（BALF） were viewed as the index of acute lung injury,which predicated to establish animal model of acute lung injury.The results showed：（1） Experimental mice in the first 2 days after infection appeared depression,ruffled fur,feed intake reduction and weight loss,while for the first three days after infection,food intake and weight reduced significantly（P0.01） compared with control group.（2） After the first three days of infection,infected mice began to die,and the mortality rate is about 62.5%（5/8）.At the same time,pulmonary edema,hemorrhage,and a number of inflammatory cells exuding from the alveolar were observed in lung of infected mice.Lung coefficient and wet weight/dry weight ratio increased significantly.（3）In the first 2 days after infection,arterial partial pressure of oxygen for infected mice began to reduce compared with that of uninfected mice,which showed significant difference in the first four days,only 6.79 kPa±1.27 kPa.Infected mice appeared serious hypoxemia,moreover,carbon dioxide separate pressure rose significantly.（4） Inflammatory cells in BALF increased significantly,especially the alveolar macrophage and polymorphonuclear leukocytosis,and from 4-8 days after infection showed extremely significant difference（P 0.01） compared with that of control group.The results showed that a mouse model of acute lung injury with H9N2 virus infection characterized by diffuse alveolar damage,severe hypoxia,and inflammation cell infiltration was established successfully in this study,which might benefit further investigation into the pathogenesis of human ALI/ARDS induced by H9N2-SIV infection.