The effects of infantile pneumonia on risk of asthma in mice

CHEN Yunxiu; TIAN Yonglu; TIAN Xiaoyin; PENG Xin; ZHANG Qiyu; LI Yuanyuan; TIAN Qinqin; ZHANG Guangli; DONG Shifang; LUO Zhengxiu

doi:10.13431/j.cnki.immunol.j.20170153

Abstract：This study was performed to investigate the effects of infantile pneumococcal pneumonia (S.pneumoniae pneumonia,S.pp) on the risk of adult asthma in mice.Three-week-old female Balb/c mice were randomly divided into 4 groups:control group (control),infantile pneumococcal pneumonia group (Inf S.pp),allergic asthma group (OVA),allergic asthma with infantile pneumococcal pneumonia group (Inf S.pp + OVA).Three-week-old Balb/c mice were infected intranasally with 25 μl pneumococcal pneumoniae at the concentration of 2 × 106 cfu/ml after anesthesia to build pneumococcal pneumonia model;while adult mice were sensitized and challenged with OVA to establish asthma model.The airway hyperresponsiveness (AHR),severity of inflammation in lung tissue,number of total cells,differential cell counts and expression of cytokines in bronchoalveolar lavage fluid (BALF),and percentages of CD4 + T cells were assayed within 24 hours after the final challenge.We found that compared with the control group,AHR was significantly increased in Inf S.pp + OVA group;the trachea,bronchus and blood vessels of lung tissue was infiltrated with a number of inflammatory cells;the number of total cells,eosinophils and neutrophils in BALF were significantly increased in Inf S.pp+OVA group (P＜0.01);the expression of IL-5,IL-13 and IL-17 were higher (P＜0.05),while IFN-γ and IL-10 were lower in Inf S.pp+OVA group (P＜0.05).Meanwhile,the percentages of Th2 and Th17 in lung tissue of Inf S.pp+OVA group were increased (P＜0.05),the percentage of Foxp3 +Treg and ratios of Th1/Th2 and Foxp3 + Treg/Th17 was decreased compared with control group (P＜0.01).While there was no significant difference in AHR,pathological changes of lung tissue,cell counts in BALF,cytokine level and percentages of CD4+ T cells between Inf S.pp+OVA group and OVA group (P＞0.05).In conclusion,infantile S.pp have no effect on the risk of asthma in adult.