目的 比较两种不同血清型肺炎链球菌致C57BL/6小鼠急性中耳炎的敏感性.方法 实验组C57BL/6小鼠经鼓膜穿刺分别接种血清型为TIGR4和6B的肺炎链球菌,对照组采用相同方法接种等体积磷酸盐缓冲液(PBS).观察小鼠发病情况,分别于感染后第1、3、5、7天制备中耳组织切片,HE染色观察中耳组织损伤及炎性细胞浸润变化,同时收集中耳灌洗液,检测灌洗液中细菌载量、炎性细胞数量和细胞因子含量.结果 6B组小鼠生存率明显低于TIGR4组和PBS对照组,差异具有统计学意义(P＜0.01).接种肺炎链球菌后,小鼠中耳灌洗液中以中性粒细胞为主,TIGR4组募集的炎性细胞数量明显多于6B组;中耳灌洗液中白细胞介素6和肿瘤坏死因子α含量明显升高,其中TIGR4组细胞因子水平均明显高于6B组;6B组小鼠中耳内的细菌清除更慢.结论 在C57 BL/6小鼠急性中耳炎模型中,6B型肺炎链球菌比TIGR4型致病性更强.%Objective To compare the sensitivities of two different serotypes of Streptococcus pneumoniae in acute otitis media of C57BL/6 mice.Methods The middle ear cavity of C57BL/6 mice were inoculated via intratympanic injection of Streptococcus pneumoniae TIGR4 or 6B 1 × 108 CFU,and the control group were inoculated equivalent phosphate buffered solution (PBS).The incidence of mice,development of otitis media and the middle ear lavage fluid pathological changes by HE staining,as well as cell counts and cytokine levels were investigated.Results After inoculated with Streptococcus pneumoniae TIGR4,6B and PBS,the survival rate of 6B group was significantly less than TIGR4 group and PBS control group (P ＜0.01).Inflammatory cells in the middle ear cavity were mainly neutrophils,and the inflammatory cells recruitment in TIGR4 group were more than 6B group; The levels of IL-6 and TNF-α in the middle ear lavage fluid in T1GR4 group and 6B group were significantly increased compared with PBS control group,while the TIGR4 group were significantly increased compared with 6B group ;6B group had delayed bacterial clearance in the middle ear.Conclusion The study implied that Streptococcus pneumoniae 6B had higher pathogenicity for acute otitis media in C57BL/6 mice than TIGR4.
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