甲型H1N1流感病毒感染对小鼠肺损伤及肠道菌群的影响

Effects of influenza A(H1N1)virus infection on lung injury and gut microbiota in mice

目的观察甲型H1N1流感病毒感染小鼠的一般状态、病毒载量、肺肠组织病理及肠道菌群的动态变化。方法用流感病毒A/PR/8(H1N1)滴鼻感染C57BL/6J小鼠,留取感染后第3、7天肺和结肠组织以及感染第0、3、7天粪便,记算肺指数,测量结肠长度、重量,采用实时荧光定量PCR法检测肺组织病毒载量,HE染色观察肺、结肠病理,16S rRNA法检测粪便菌群。结果感染组较空白组小鼠体重减轻,活动减少,第3天肺组织病毒载量显著升高,肺指数升高,肺病理出现损伤,结肠长度缩短,结肠病理未见明显损伤;第7天肺病毒载量有所下降,肺指数显著升高,肺组织病理损伤严重,结肠长度进一步缩短,结肠病理未见显著炎症。感染后第3天粪便菌群乳酸菌丰度下降,第7天乳酸菌属丰度显著下降,志贺菌、肠球菌属显著升高。结论甲型流感病毒感染导致小鼠进食量减少、体重降低、肺组织病毒载量升高、肺组织病理损伤,同时引起结肠长度缩短,肠道菌群失调。

Objective To investigate the dynamic changes of general status,lung tissue viral loads,pulmonary and intestinal histopathology and gut microbiota in mice infected with influenza A virus.Methods C57BL/6J mice were infected intranasally with influenza virus A/PR/8(H1N1).Lung and colon tissue of the mice were collected on day 3 and day 7 after infection.Stool samples of the mice were collected on day 0,3 and 7 after infection.The lung indexes were calculated,and the lengths and weight of colon were measured.The viral loads in lung tissue were detected by real-time quantitative PCR(RTqPCR).Pathological changes of lung and colon tissue were detected by HE staining.The micorbiota in the stool samples were sequenced by using the V3-V4 variable region of 16S rRNA.Results Compared with control group,the body weight and activities of mice in infection group decreased.On day 3 after the infection,compared with control group,the lung viral loads and lung index were significantly higher,the lung pathological injury occurred,and the colon length was shorter without remarkable colon pathology injury in the mice in infection group.On day 7 after infection,the lung viral loads in infected mice decreased compared with those on day 3 after infection.The lung index further increased,the lung pathological injury became more severe and the colon length further decreased compared with control group.No obvious colon pathology change(inflammation)was observed.On day 3 after infection,the abundance of Lactobacillus decreased in gut microbiota.On day 7 after infection,the abundance of Lactobacillus significantly decreased,the abundances of Shigella and Enterococcus remarkably increased in gut microbiota.Conclusion Mice infected with influenza A virus would exhibit weight loss,reduced intake,increased lung viral titers,lung pathological injury,shortened colon length,and gut microbiota alteration.