Role Of Interleukin-23and Interleukin-21in The Asthmatic Airway Inflammation

PART I Establishment of murine asthma model and effects of two different methods of challenge on airway inflammationObjective: To establish murine asthma model and investigate the effects of two different methods of challenge, intranasal or aerosol exposure, on airway inflammation.Methods:BALB/c mice were primed with OVA and then were challenged to set up murine model of atopic asthma by intranasal or aerosol exposure to OVA. Then the leukocytes and cell classifications in broncho alveolar lavage fluid(BALF) was measured. IL-4, IL-13concentration in BALF were determined by ELISA and the extent of histological changes in lung was studied.Results:The total leukocytes in intranasal group were highest. The levels of eosinophil and neutrophil in intranasal group were higher than that in aerosol exposure group and normal group. The difference was statistical significance (P<0.05). The levels of IL-4and IL-13in intranasal group were higher than that in aerosol exposure group and normal group. The difference was statistical significance (P<0.05). The lung tissue inflammation pathological change in intranasal group was most obvious with destruction of the epithelial cells, goblet cells hyperplasia and more eosinophils and lymphocytes infiltration of the peribronchi and vessels than that in aerosol exposure group and normal group.Conclusion:Asthmatic model can be established successfully by both of nasal challenge and aerosol challenge and the intranasal administration trigger more obvious airway inflammation and higher cytokines expression than aerosol challenge. PART II Blockade of IL-23ameliorate allergic lung inflammation via decreasing the infiltration of Tc17cellsObjective:Tc17cell is IL-17-producing CD8+T cells and have been found to participate in the development of allergic asthma. IL-23is a cytokine that may be involved in modulating IL-17response via Th17cells. This study aimed to investigate whether IL-23also has the immunomodulatory effects on Tc17cells.Methods:Female BALB/c mice (6-8weeks old) were divided into4groups according to sensitization/challenge/treatment:1) normal control group,2) asthma group,3) Anti-IL-23antibody group, and4) Isotype antibody group. Allergic asthmatic mouse model was induced by sensitizated and challenged with ovalbumin (OVA). Anti-IL-23antibody or isotype antibody was administrated intratracheally before challenge to OVA-induced asthmatic mouse model. Airway hyperresponsiveness was determined by using the FlexiVent system. Inflammation cells counting in BALF and lung sections stained with hematoxylin and eosin (H&E) and periodic acid-Schiff (PAS) stain were determined. Tc17cells percentages and IL-17level in the lung tissue homogenate were measured.Results:Anti-IL-23treatment reduced airway hyperresponsiveness, inflammation cells infiltration in BALF, airway inflammation and mucus secretion. Treatment with anti-IL-23antibody also markedly reduced IL-17level, Th17and Tc17cells percentage in lung tissue homogenate.Conclusions:Our data suggest that IL-23/Tc17cells axis may be involved in the pathogenesis of asthma as the complement of IL-23/Th17cells. PART III Exclusion of IL-21in the pathogenesis of OVA-induced asthma in miceObjective: Cytokines, especially T helper2-derived cytokines interleukin (IL)-4, IL-5, and IL-13, are involved in the pathogenesis of asthma. IL-21, a member of the type I cytokine family with significant sequence homology to IL-4, has a variety of effects on the immune system. However, the contribution of IL-21to the development of allergic diseases is currently controversial. The aim of this study was to investigate the effect of IL-21on asthma airway inflammation in vivo.Methods:A murine ovalbumin (OVA)-induced allergic asthma model was used. The concentration of IL-21in the bronchoalveolar lavage fluid (BALF) of mice was evaluated by enzyme-linked immunosorbent assay. BALF cellularity, lung histopathology, and sera IgE levels were compared between the normal control group, OVA sensitization/challenge group, and OVA sensitization/challenge plus IL-21-administered group. An OVA-induced allergic rhinitis model with IL-21was used as a positive control and the infiltration of eosinophils in the nasal mucosa was evaluated.Results:The concentration of IL-21in the BALF was lower in the asthmatic group compared with the normal control group. However, no significant differences in airway eosinophilia, lung histopathology, and sera IgE levels were observed between the OVA sensitization/challenge group and OVA sensitization/challenge plus IL-21-administered group. Decreased eosinophilic infiltration in nasal mucosa was observed in the positive control allergic rhinitis model administered IL-21during the challenge period.Conclusion:Exogenous administration of IL-21alone may not alleviate allergic lung inflammation.The role of IL-21in allergic lung inflammation needs further research.