环境低温对H9N2亚型禽流感病毒感染小鼠致病性的影响

Effects of low ambient temperature on the pathogenicity of H9N2 subtype avian influenza virus in infected mice

旨在分析环境低温对H9N2亚型禽流感病毒感染小鼠致病性的影响。选用120只6~8周龄,雄性SPF BALB/c小鼠,随机分为4组:无感染常温组(PBS处理,(20±2)℃)、无感染低温组(PBS处理,(10±2)℃)、H9N2病毒感染常温组(H9N2处理,(20±2)℃)、H9N2病毒感染低温组(H9N2处理,(10±2)℃)。在感染后观察感染小鼠发病14d内的临床症状、存活率,肺脏病变程度、肺部细胞因子含量的动态变化以及肺脏病毒载量。结果表明:1)与H9N2病毒感染常温组小鼠相比,环境低温处理的H9N2病毒感染小鼠临床症状明显加重,其中体重明显降低,但差异不显著(P>0.05),存活率由95%降为67%,肺水肿程度和肺组织病变程度更加严重;2)H9N2病毒感染低温组与H9N2病毒感染常温组相比,肺脏TNF-a和IL-1β含量无显著差异,但均显著高于2个无感染组(P<0.01);3)H9N2病毒感染低温组与H9N2病毒感染常温组相比,肺组织病毒载量显著增加(P<0.01)。综上,环境低温明显增加了H9N2亚型流感病毒对小鼠的致病性,为进一步揭示环境低温与流感病毒感染之间的关系,以及采取有效的预防措施提供数据基础。

The aim of this study was to analyze the effect of low ambient temperature on H9N2 influenza virus infection in mice.A total of 120 male 6-8 weeks old SPF BALB/c mice were randomly assigned into 4 groups:room temperature group without infection(PBS,(20±2)℃),cold treatment group without infection(PBS,(10±2)℃),room temperature group with H9N2 infection(H9N2,(20±2)℃)and cold treatment group with H9N2 infection(H9N2,(10±2)℃).After infection,the clinical symptoms,mortality,pulmonary pathological changes,the degree of pulmonary edema,the level of cytokines of lung and viral titers of lung were observed.The results indicated that:1)Compared with H9N2 virus infected mice in normal temperature group,the clinical symptoms of H9N2 virus infected mice in low temperature were significantly aggravated,and the body weight was significantly reduced,the survival rate was reduced from 95%to 67%,and the degree of pulmonary edema and lung tissue were more serious;2)There was no significant difference in the levels of TNF-αand IL-1βbetween the two groups,but they were significantly higher than that in the non-infected mice(P<0.01);3)Compared with the normal temperature group,the viral load in lung tissue of H9N2 virus infected hypothermia group was significantly increased(P <0.01).In conclusion,low ambient temperature could aggravate the severity of H9N2 influenza virus infection in mice.This study will help us further understand the relationship between low ambient temperature and influenza virus infection,and take effective measures to prevent influenza infection.