The Study Of Bifidobacterium Infantis’ Preventive Effect On Allergic Asthma And Food Allergy Mouse

Part One:The Study of Bifidobacterium infantis’ Preventive Effect on a Allergic Asthma Mouse ModelObjective: To investigate the preventive effect and immunomodulatory mechanism of Bifidobacterium infantis on allergic asthma mouse model.Methods: 40 Male BALB/c mice were randomly divided into 4 groups: normal control group, allergic asthma group, Bifidobacterium infantis prevention group and treatment group. Mice were sensitized with intraperitoneal injection of OVA on days 7and14, then challenged with 1% OVA aerosol in saline between days 22 and 28. Bifidobacterium infantis was administered daily by the oral route in the prevention group from day1 to 14 and the treatment group from day15 to 28. After antigen challenge Clinical symptoms, Total bronchoalveolar lavage fluid cells, pulmonary airway inflammation were assessed, Levels of OVA specific Ig E, Ig G1, interleukin(IL)-4, IL-5, IL-13, IL-10 and Interferon(IFN)-γ were quantified using ELISA kit.Results:(1) Allergic asthma group showed varying degrees of sneezing, shortness of breath, loss of appetite. Bifidobacterium infantis supplemented groups have shown improved allergy symptoms.(2) The numbers of total inflammatory cells was significantly increased in the BALF of the allergic asthma group, the numbers of cells was significantly decreased in the Bifidobacterium infantis prevention group and treatment group.(3) The peribronchial and perivascular infiltration of inflammatory cells was heavier in allergic asthma group, sever inflammatory changes were not observed in prevention group and treatment group.(4) The OVA-specific Ig E and Ig G1 levels of the allergic asthma group were significantly higher, Bifidobacterium infantis were significantly decreased the levels of OVA-specific Ig E and Ig G1 in the prevention group and treatment group.(5) The cyto-kines IL-4 and IL-13 of BALF were significantly higher, and IL-10 of serum was lower in the allergic asthma group, Bifidobacterium infantis could significantly inhibit IL-4 and IL-13 production in prevention group and treatment group, and enhance the production of IL-10 in treatment group.Conclusion:(1) The higher Th2 cytokines, IL-4 and IL-13, and lower regulatory T cell(Treg) cytokine IL-10 in allergic asthma mouse, suggesting that OVA allergic asthma can distrube the Th2/Treg balance.(2) The results suggest that orally administered Bifidobacterium infantis can inhibit OVA specific Ig E and Ig G1 production and suppress the allergic reaction,and restore immune homeostasis mainly through suppressing the Th2 cytokines production, such as IL-4 and IL-13, and increasing the Treg cytokines IL-10.Part Two:The Study of Bifidobacterium infantis’ Preventive Effect on a Food Allergy Mouse ModelObjective: To investigate the preventive effect and immunomodulatory mechanism ofBifidobacterium infantis on food allergy mouse model.Methods: 40 Male BALB/c mice were randomly divided into 4 groups: normal control group, Food Allergy group, Bifidobacterium infantis prevention group and treatment group. Mice were sensitized with BLG on days 7, 14 and 21, then orally challenged with BLG on days 28. Bifidobacterium infantis was administered daily by the oral route in the prevention group from day 1 to 21, and the treatment group from day15 to 28. After antigen challenge Clinical symptoms, inflammatory damage to the intestinal were assessed. Levels of totle Ig E, IL-4, IL-5, IL-13, IL-10 and IFN-γ were quantified using ELISA kit.Results:(1) Food allergy group was showed varying degrees of loss of appetite and weight, hair erected dull, Bifidobacterium infantis supplemented groups were shown less allergy symptoms.(2) The weight was decreased in food allergy group, but increased in the Bifidobacterium infantis supplemented groups, however, it was much higher in the treatment group.(3) The inflammatory damage to the intestinal was significantly heavier in food allergy group, Bifidobacterium infantis could eliminated the inflammatory damage to the prevention group and treatment group.(4) The level of serum totle Ig E in the food allergy group was higher.The level of Ig E in prevention group and treatment group were significantly decreased, the treatment group was much lower than the prevention group.(5) The serum cytokines IL-4 and IL-13 were significantly higher, and IL-10 in was lower in the food allergy group. Bifidobacterium infantis was inhibited the IL-4 and IL-13 production in prevention group, and inhibited the IL-13 production in treatment group. however, there were no difference between the food allergy group and Bifidobacterium infantis supplemented groups in the production of IL-10.Conclusion:(1) The higher levels of Th2 cytokines, such as IL-4 and IL-13, and lower level IL-10 in food allergy mouse, suggest food allergy distrube the Th2/Treg balance.(2) The results suggest that Oral administration of Bifidobacterium infantis can inhibit Ig E production and suppress the allergic reaction,and decrease the production of Th2 cytokines, such as IL-4 and IL-13, but there is no effect on the regulatory cytokines IL-10.