Abstract
Background- While ovalbumin (OVA) sensitization is an often used asthma model in mice, house dust mite (HDM) sensitization is of the most relevant clinically. However the respective role of lung compartments in the occurrence of HDM-induced bronchospasm is poorly understood.
Objectives- To evaluate the respiratory impedance during the early phase of allergic response in mice sensitized to HDM compared to OVA.
Methods- BALB/c mice were randomized into naïve or sensitized groups (OVA: 50µg+2mg alum/200µL intraperitoneal injection on days 0 and 7, 60µg/20µL intranasal instillations on days 14-17; HDM: 6x 25µg/20µL intranasal instillations over 2 weeks). After sensitization, mice were anesthetized and mechanically ventilated. Forced oscillatory respiratory mechanics (airway resistance (Raw), tissue damping (G) and elastance (H)) were assessed before and over 15 minutes (15') following allergen challenge.
Preliminary results- After OVA challenge in OVA sensitized mice, the marked Raw response peaking at 15' (% baseline 128±48 p<0.001) dominated over the peripheral response, which peaked at 7' (G 42±16%, H 46±26% p<0.05). Conversely, in HDM sensitized mice, marked increase in G and H observed 7' after HDM challenge (G 24±26%, H 33±28%) was higher than the response in Raw (20±15%). Naïve mice did not respond to allergens.
Conclusions- Mice sensitized with OVA or HDM presented different patterns of allergic lung response. While OVA challenge led primarily to airway response with subsequent development of ventilation heterogeneities, HDM challenge compromised predominantly the viscoelastic properties of the lung.
Supported by SNSF grant 332003B-143331/1.
- © 2014 ERS