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目的探讨婴儿型双歧杆菌对气道过敏小鼠的气道炎症作用及其机制。方法 6周龄BALB/c雄性小鼠40只,随机分为4组:阴性对照组、哮喘组、婴儿型双歧杆菌预防组和婴儿型双歧杆菌治疗组。哮喘组、预防组和治疗组用卵清蛋白(Ovalbvmin,OVA)进行致敏和激发诱发哮喘,阴性对照组用生理盐水进行致敏和激发。预防组第0至14天灌胃菌液;治疗组第15至28天灌胃菌液;阴性对照组和哮喘组全程灌胃生理盐水作对照。观察小鼠气道过敏表现;计数肺泡灌洗液(Bronchoalveolar lavage fluid,BALF)中细胞总数评估气道炎症程度;肺组织行HE染色;ELISA法测定血清中IL-10、OVA特异性IgE和OVA特异性IgG1的浓度以及肺泡灌洗液中细胞因子IL-4、IL-5、IL-10、IL-13和IFN-γ的浓度。结果 (1)哮喘组小鼠在激发后出现搔抓口鼻、竖毛、打喷嚏、腹肌扇动、弓背直立、二便失禁以及体重下降等表现,预防组和治疗组的症状较轻。(2)预防组和治疗组BALF细胞数量明显低于哮喘组(P<0.05)。(3)肺组织HE染色后,哮喘组小鼠肺组织出现明显的炎症细胞浸润,预防组和治疗组肺组织炎症明显减轻。(4)预防组和治疗组血清OVA特异性IgE浓度明显低于哮喘组(P<0.05),并且预防组低于治疗组(P<0.05);治疗组血清OVA特异性IgG1浓度明显低于哮喘组和预防组(P>0.05);预防组和治疗组血清IL-10浓度明显高于哮喘组(P<0.05),且治疗组高于预防组(P<0.05);(5)预防组和治疗组肺泡灌洗液中IL-4、IL-13含量明显低于哮喘组(P<0.05);IL-5、IL-10、IFN-γ各组浓度都较低,未测出有效浓度。结论口服婴儿型双歧杆菌可以减轻过敏症状,降低肺组织炎症浸润程度,抑制Th2免疫反应。
Objective To investigate the effect and mechanism of infant Bifidobacterium on airway inflammation in airway allergic mice. Methods Forty BALB / c male mice of 6 weeks old were randomly divided into 4 groups: negative control group, asthma group, Bifidobacterium infantis prophylaxis group and Bifidobacterium infantis group. The asthmatic group, prophylaxis group and treatment group were sensitized and challenged with ovalbumin (OVA) to induce asthma. The negative control group was sensitized and challenged with saline. In the prevention group, the bacteria were inoculated on the 0th to the 14th day; the bacteria in the treatment group was inoculated on the 15th to 28th days; the normal control group and the asthma group were given the normal saline as the control. The airway hypersensitivity of mice was observed. The number of airway inflammation in bronchoalveolar lavage fluid (BALF) was counted to evaluate the degree of airway inflammation. The lung tissue was stained with HE. The serum levels of IL-10, OVA-specific IgE and OVA The concentration of specific IgG1 and the concentrations of cytokines IL-4, IL-5, IL-10, IL-13 and IFN-γ in BALF. Results (1) Mice in asthmatic group showed mild symptoms of scratching nose and mouth, vertical hair, sneezing, abdominal muscle flap, erect bow, incontinence and weight loss. (2) The number of BALF cells in prevention group and treatment group was significantly lower than that in asthma group (P <0.05). (3) After the lung tissue was stained by HE, the inflammatory cell infiltration in the lung tissue of the asthmatic group was obvious, and the inflammation of the lung tissue in the prevention group and the treatment group was obviously relieved. (4) Serum concentration of OVA-specific IgE in prevention group and treatment group was significantly lower than that in asthma group (P <0.05), and the prevention group was lower than the treatment group (P <0.05); serum OVA-specific IgG1 concentration in the treatment group was significantly lower than that in the asthma group (P <0.05). The concentration of serum IL-10 in prevention group and treatment group was significantly higher than that in asthma group (P <0.05), and the treatment group was higher than the prevention group (P <0.05). (5) The levels of IL-4 and IL-13 in the bronchoalveolar lavage fluid in the treatment group were significantly lower than those in the asthma group (P <0.05). The concentrations of IL-5, IL-10 and IFN-γ in each group were lower and no effective concentration was found. Conclusion Oral infantile bifidobacterium can relieve allergy symptoms, reduce inflammatory infiltration of lung tissue and inhibit Th2 immune response.