MODELLING OF BRONCHIAL ASTHMA WITH NEUTROPHILIC PHENOTYPE OF INFLAMMATION
The aim of this study was to create a mouse model of neutrophilic asthma using model allergen ovalbumin (OVA) and different types of lipopolysaccharides (LPS). Mice BALB/c were divided into 7 groups. Group 1 was i.p. immunized with mixture of OVA and Al(OH)3 3 times in two week intervals and challenged on days 41, 42, 43 with OVA only. Group 2 was s.c. immunized with mixture of OVA and Complete Freund’s adjuvant (CFA) and Incomplete Freund’s adjuvant (IFA) 3 times in two week intervals and then challenged on days 41, 42, 43 by aerosol administration with mixture of OVA and LPS obtained from S. sonnei. Groups 3 and 4 were sensitized by the same manner but challenged with mixture of OVA and LPSs obtained from K. pneumonia and C. auroginosa, respectively. Group 5 was used as a negative control where mice were immunized and challenged with PBS only. Groups 6 and 7 were s.c. immunized with mixture of OVA and CFA and challenged on days 22 and 23 with OVA only (group 6) or OVA together with LPS obtained from E.coli (group 7). Twenty-four hours after the final challenge, airway hyperresponsiveness (AHR) to methacholine was measured using whole body plethysmography. 48 hours after the final challenge bronchoalveolar lavage (BAL) was collected for cells differential count and lungs were removed for histological examination. Anti-OVA IgE, IgG1 and IgG2a in sera collected after the challenge were detected by ELISA. AHR to increasing concentrations of methacholine in groups 1-4 and 6, 7 was moderately increased in compare to control group 5. Anti-OVA IgE was at high level in all experimental groups in comparison to control group 5. At the same time in groups 2, 3, 4 anti-OVA IgE was lower than that of group 1. Anti-OVA IgG1 and IgG2a were at highest levels in groups 1, 2, 3, 4 if compare to group 5. Analysis of cell composition in BAL demonstrated an increase of eosinophils in group 1 compared to control group 5. While in groups 2, 3, 4 a significant increase of neutrophils in compare to groups 1 and 5 was observed. General presentation of allergic inflammation in the lungs of mice groups 1-4 and 6, 7 was more pronounced as compared to control group 5. Peribronchial and perivascular infiltration with eosinophils observed in group 1 only while in groups 2, 3, 4 the number of neutrophils in peribronchial and perivascular infiltrates was significantly increased in compare to control group 5 or group 1. These data indicate that sensitization of mice with allergen together with CFA and consequently challenge with specific allergen together with LPSs leads to formation of neutrophilic type of allergic inflammation in the lungs.