Alteration In Lung Protection Barrier During Avian-origin Influenza A (H7N9) Virus Infection

Objective: This research had monitored the changes of mucins,tight junction protein and surfactant protein in lung infected with H7N9 virus and control group by molecular biological technique,thus to explore the alteration of airway mucous ciliary clearance function,the lung epithelial barrier function and the stability of alveolar structure.Method: Retrospectively analyse the personal data,clinical manifestations,laboratory tests and so on,of the cases of H7N9 patients,providing a certain basis of the diagnosis and the treatment of the disease.Compare the pathological changes of lung,liver and myocardium between H7N9 group and control group with HE staining.Meanwhile,compare the expression of mRNA of mucins,tight junction protein and surfactant protein by RT-PCR,thus preliminary studing the alteration of airway mucous ciliary clearance function,the lung epithelial barrier function and the stability of alveolar structure in lung infected H7N9 virus.Results:(1)All of the 4 patients,collected in this study,had the history of poultry contact.And all of them had basic diseases and belong to middle and old age group.Their main clinical manifestations included high fever,cough,shortness of breath,dyspnea,chest distress,chest pain,hemoptysis,abdominal pain,etc.All of the 4 patients suffered from septic shock and ARDS,and could also have acute renal injury,encephalopathy and rhabdomyolysis.The chest X-ray and chest CT of the 4 patients showed bilateral pulmonary consolidation and Ground-Glass Opacity,even combined with the single or bilateral pleural effusion.All of the 4 patients present lymphocytopenia and thrombocytopenia.(2)When infected with the H7N9 virus,pulmonary alveolar hemorrhage and fibrous tissue hyperplasia followed can be seen in the lung;there are many vacuolar fatty degeneration in the liver.The relative mRNA expression of airway mucins MUC2,MUC5 B and MUC5 AC may be increased.The relative expression of mRNA was decreased in CLDN1,CLDN5,CLDN7 and CLDN8,and the relative expression of CLDN3 mRNA was significantly increased.The relative expression of SFTPA,SFTPC and SFTPD mRNA was significantly decreased,while SFTPB mRNA was significantly increased.Conclusions:(1)The infection of H7N9 virus was closely associated with direct contact with poultry or the water of poultry contamination.The H7N9 virus is more easier to infect the middle old-age,especially those with basic diseases,which may be related to their low immune function.The main clinical manifestations include persistent fever,cough and dyspnea and so on,and can be rapidly developed into septic shock,ARDS,acute renal impairment,etc.The chest imaging findings in patients infected with H7N9 virus are single or bilateral pulmonary consolidation and ground-glass opacity;laboratory examination can present lymphocytopenia and thrombocytopenia.(2)The typical pulmonary pathology of patients infected with H7N9 virus are acute diffuse alveolar injury and massive pulmonary alveolar cell,alveolar interstitial hemorrhage and diffuse pulmonary injury in the later period.The lung defense barrier of airway mucous ciliary clearance function and lung epithelial cell barrier function,the stability of alveolar structure may change when infected H7N9 virus.In brief,there are certain characteristics of the epidemiology of H7N9 virus infection.The pulmonary pathology is significantly.The lung defense barrier of airway mucous ciliary clearance function and lung epithelial cell barrier function,the stability of alveolar structure may change when infected H7N9 virus.