鼻内滴入罗伊氏乳杆菌TR02减轻肺炎支原体诱导的小鼠肺部炎症损伤

Intranasal administration of Lactobacillus reuteri TR02 attenuates Mycoplasma pneumoniae-induced lung inflammatory response in mice

目的探讨经鼻滴入罗伊氏乳杆菌TR02(Lactobacillus reuteri TR02,Lr TR02)对BALB/c小鼠呼吸道肺炎支原体(Mycoplasma pneumoniae,Mp)感染的免疫调节。方法小鼠随机分2组,分别连续2 d经鼻滴入PBS或Lr TR02,第3天经呼吸道感染2×107菌落形成单位的Mp。Mp感染后第3天处死小鼠,固体培养和定量PCR检测肺组织匀浆中Mp载量,病理切片HE染色分析肺组织炎症,流式细胞术对外周血进行细胞分类及计数,ELISA检测促炎细胞因子TNF-α、IL-6、IL-8、IL-17A和抑炎细胞因子IL-10的水平。结果预先经鼻滴入Lr TR02不影响Mp感染第3天小鼠肺组织Mp载量,但可阻止Mp感染引起的小鼠体重减轻,并显著减轻肺组织炎症。与对照组比较,经鼻滴入Lr TR02小鼠感染Mp后外周血中性粒细胞数量和比例减少,肺组织髓过氧化物酶(MPO)活性降低,肺组织TNF-α、IL-8和IL-17A的分泌水平降低,IL-10的表达增加,但未显著影响IL-6的产生。结论经鼻滴入Lr TR02可减少Mp感染小鼠中性粒细胞浸润和MPO活性,减少TNF-α、IL-8和IL-17A的分泌,增加IL-10的产生,减轻感染早期肺组织炎症损伤。

Objective To investigate the effect of intranasal administration of Lactobacillus reuteri TR02(Lr TR02)on Mycoplasma pneumoniae(Mp)-induced inflammation reaction in BALB/c mice.Methods Fourteen mice were randomly divided into two groups and intranasally treated with PBS or Lr TR02 for two consecutive days.Then they were infected with 2×107 colony-forming units of Mp through airway.The mice were sacrificed at 3 d after infection.The loads of Mp in lung tissues were analyzed by culturing and quantitative PCR.Histopathological injury in lung tissues was observed after HE staining.Peripheral blood cells were counted and classified by flow cytometry analysis.ELISA was performed to detect the secretion of pro-inflammatory cytokines TNF-α,IL-6,IL-8 and IL-17A as well as anti-inflammation cytokine IL-10.Results Intranasal administration with Lr TR02 prevented weight loss and significantly alleviated the pulmonary inflammation in mice,but had no influence the loads of the pathogen in mouse lung tissues at 3 d after Mp infection.Compared with the control group,pre-treatment with Lr TR02 decreased the number and percentage of peripheral blood neutrophils,inhibited myeloperoxidase activity,reduced the secretion of TNF-α,IL-8 and IL-17A,and promoted the production of IL-10 in the lung tissues of mice with Mp infection.However,it had no significant influence on the expression of IL-6.Conclusions Intranasal administration with Lr TR02 could attenuate mouse lung inflammatory injury in the early stage of Mp infection by reducing neutrophil infiltration,inhibiting myeloperoxidase activity,decreasing the secretion of TNF-α,IL-8 and IL-17A,and increasing the expression of IL-10.