抗生素诱导的呼吸道菌群缺失对小鼠RSV感染的影响

Effect of respiratory microbiota depletion induced by antibiotics on RSV infection in mice

目的探究抗生素雾化暴露引起的呼吸道菌群缺失对小鼠呼吸道合胞病毒(RSV)感染的影响,为临床合理使用抗生素提供指导意见。方法32只BALB/c小鼠分为2组:雾化ddH_(2)O对照组和雾化ABX组合抗生素组,处理6 d后,进行细菌16S rRNA基因PCR检测,构建呼吸道菌群缺失小鼠模型。上述2组组内再随机分为2小组,即PBS对照组(ddH_(2)O+PBS,ABX+PBS)和RSV感染组(ddH_(2)O+RSV,ABX+RSV),饲养至第14天。检测和分析各组小鼠支气管肺泡灌洗液(BALF)中的炎症细胞和相关细胞因子(TNF-α、IL-8、IL-10及MCP-1)的数量和水平,观察肺组织病理学状况及检测病毒载量。结果BALF中细菌DNA提取和16S rRNA基因PCR检测显示,雾化ABX组合抗生素处理能够有效地剔除呼吸道菌群。BALF中炎症细胞和相关细胞因子检测显示,ABX+RSV组炎症细胞总数明显增多(P<0.05),分类以巨噬细胞和淋巴细胞为主;且细胞因子TNF-α、IL-8、MCP-1及IL-10水平显著升高(均P<0.05)。肺部HE染色显示,感染RSV后ddH_(2)O+RSV组和ABX+RSV组小鼠肺部损伤明显加重(均P≤0.01),与ddH_(2)O+RSV组相比较,ABX+RSV组的病毒载量明显升高(t=2.7160,P=0.0217)。结论雾化ABX组合抗生素不仅能够有效地剔除呼吸道菌群,而且明显增加了小鼠感染RSV的风险,导致呼吸道炎症加重,以及病毒载量升高。

Objective To explore the effect of respiratory microbiota depletion induced by antibiotics on respiratory syncytial virus(RSV)infection in mice,and provide guidance for the rational use of antibiotics in clinical practice.Methods Thirty-two BALB/c mice were divided into two groups:the control group treated with nebulized ddH_(2)O and the treatment group treated with nebulized antibiotics cocktails(ABX).After 6 days of treatment,the bacterial 16 S rRNA gene was amplified by PCR and the mouse models of respiratory microbiota depletion were established.The two groups were then randomly divided into two sub groups respectively,namely PBS control groups(ddH_(2)O+PBS,ABX+PBS)and RSV infection groups(ddH_(2)O+RSV,ABX+RSV),and fed for 14 days.The counts and levels of inflammatory cells and related cytokines(TNF-α,IL-8,MCP-1 and IL-10)in BALF were measured.The histopathology and viral load of lung were observed.Results Treatment with nebulized ABX effectively eliminated respiratory bacteria.The detection of inflammatory cells and related cytokines in BALF showed that total inflammatory cells significantly increased(P<0.05),mainly consisting of macrophages and lymphocytes,in ABX+RSV and ddH_(2)O+RSV groups.The levels of TNF-α,IL-8,MCP-1 and IL-10 also significantly increased(all P<0.05).H&E staining showed that the lung injury was significantly aggravated after RSV infection in ddH_(2)O+RSV and ABX+RSV groups(all P≤0.01),and the viral load in ABX+RSV group significantly increased compared with ddH_(2)O+RSV group(t=2.7160,P=0.0217).Conclusion Nebulized ABX antibiotics not only effectively eliminate the respiratory tract flora,but also significantly increase the risk of RSV infection,resulting in severer respiratory inflammation and higher viral load of RSV in mice.