Acute respiratory distress syndrome induced by H9N2 virus in mice.
H9N2 avian influenza viruses have repeatedly caused infections in swine and humans in some countries. The purpose of the present study was to evaluate the pulmonary pathology caused by H9N2 viral infection in mice. Six- to eight-week-old BALB/c mice were infected intranasally with 1 x 10(4) MID(50) of A/Chicken/Hebei/4/2008(H9N2) virus. Clinical signs, pathological changes and viral replication in lungs, arterial blood gas, and cytokines in bronchoalveolar lavage fluid (BALF) were observed at different time points after infection. A control group was infected intranasally with noninfectious allantoic fluid. H9N2-infected mice exhibited severe respiratory syndrome, with a mortality rate of 60%. Gross observations showed that infected lungs were highly edematous. Major histopathological changes in infected lungs included diffuse pneumonia and alveolar damage, with neutrophil-dominant inflammatory cellular infiltration, interstitial and alveolar edema, hemorrhage, and severe bronchiolitis/peribronchiolitis. In addition, H9N2 viral infection resulted in severe progressive hypoxemia, lymphopenia, and a significant increase in neutrophils, tumor necrosis factor-alpha and interleukin-6 in BALF. The features described above satisfy the criteria for acute respiratory distress syndrome (ARDS). Our data show that H9N2 viral infection resulted in ARDS in mice, and this may facilitate studies of the pathogenesis of future potential H9N2 disease in humans.
Deng
Guangcun
G
Department of Pathophysiology, College of Veterinary Medicine, China Agricultural University, 100193, Beijing, People's Republic of China.
Bi
Jianmin
J
Kong
Fuli
F
Li
Xuezhu
X
Xu
Qiang
Q
Dong
Jun
J
Zhang
Miaojie
M
Zhao
Lihong
L
Luan
Zhihua
Z
Lv
Nana
N
Qiao
Jian
J
D000818:Animals; D001784:Blood Gas Analysis; D055745:Bronchioles / Q000473:pathology; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D016207:Cytokines / Q000032:analysis; D005260:Female; D006470:Hemorrhage / Q000473:pathology; D000860:Hypoxia; D053127:Influenza A Virus, H9N2 Subtype / Q000472:pathogenicity*; D008168:Lung / Q000473:pathology* / Q000821:virology*; D017563:Lung Diseases, Interstitial / Q000473:pathology; D008231:Lymphopenia; D051379:Mice; D008807:Mice, Inbred BALB C; D009504:Neutrophils / Q000276:immunology; D009976:Orthomyxoviridae Infections / Q000401:mortality / Q000473:pathology / Q000821:virology; D011014:Pneumonia / Q000473:pathology / Q000821:virology; D011650:Pulmonary Alveoli / Q000473:pathology; D012128:Respiratory Distress Syndrome / Q000473:pathology* / Q000821:virology*
D016207:Cytokines