Comparative study of acute and chronic murine asthma model in the pathogenesis of asthma

Objective To explore the differences in airway inflammation, airway remodeling and airway hyperresponsiveness of ovalbumin (OVA) induced murine asthma model during acute and chronic terms, and clear the pathological changes in the pathogenesis of asthma. Methods 48 BALB/c mice were randomly divided into acute and chronic groups, in which acute groups including normal control group (A1 group) and acute asthma group (A2 group), chronic group including normal control group (B1 group) and chronic asthma group (B2 group). Using OVA sensitized and challenged methods induced acute and chronic asthma model, then assessed the airway resistance, total cell numbers and different cell numbers in the BALF, and detected the levels of IL-4, IL-5, transforming growth factor-β1 (TGF-β1), vascular endothelial growth factor (VEGF) and IFN-γ by enzyme-linked immunosorbent assay (ELISA). Then HE staining was used to observe airway inflammation.AB-PAS and Masson staining were used to measure airway remodeling. Results Compared with normal mice, the airway resistance of the acute asthma group and the chronic asthma group were significantly increased, there was no difference between the two groups, but the basic airway resistance in the chronic phase was significantly changed.Compared to the chronic asthmatic mice, the inflammatory changes, such as numbers of total cells and EOS cells, levels of IL-4, IL-5 and IFN-γ, aggregation of inflammatory cells around the airway and vascular and secretion of airway mucus were more obvious during acute phase.However, changes such as the levels of TGF-β1 and VEGF in the BALF, the thickening of airway smooth muscle, the subepithelial collagen deposition and subepithelial fibrosis were more significant in the chronic phase when compared with the acute asthma group. Conclusions In the early stage of asthma is mainly inflammatory changes, but the mild remodeling changes have been presented during this stage.And in the chronic stage of asthma although the inflammatory changes are continued, but the mainly factors that impact asthma symptoms are the organic changes. Key words: Asthma model; Acute asthma; Chronic asthma; Airway inflammation; Airway remodeling