IgE-mediated upper airway inflammation in a russian thistle pollen-induced murine model

Abstract

Allergic rhinitis (AR) has worldwide distribution with an increasingprevalence every year. Also, allergic rhinitis and chronic rhinosinus-itis are frequently associated with asthma. In our region, Russianthistle (Salsola kali) is a common weed causing pollinosis. The aimof this study was to establish a mouse model of AR based on Salsolakali pollen proteins, and to define the extent that this could have inthe lower airways. BALB/c mice (n = 5/group) were administratedweekly with PBS or S. kali pollen extract through i.p. route and lat-er challenged by nasal instillation of PBS or S. kali pollen respec-tively on days 21, 22 and 23. Bronchoalveolar lavage (BAL) wereobtained. Serum total IgE and S. kali-specific IgE were measuredby ELISA. After sacrifice, the noses and lungs were fixed and par-affin embedded for histological analysis (H&E, toluidine blue and periodic acid-Schiff). After nasal challenge, frequency of sneezingin sensitized group were higher than the control (p<0,001). Gobletcell hyperplasia and eosinophil infiltration was observed in nasal lat-eral mucosa (257±40 in sensitized mice vs. 16±2 in control group,p<0,05). IgE values were increased seven times in sensitized micecompared to control group (p<0,01). Moreover, mice in the sensi-tized group had significantly higher levels of S. kali-specific IgE thanthe control (p<0,05). Sensitization induced moderate to severe in-flammatory infiltration in lungs. Significant increased number of totalinflammatory cells were observed in BAL from sensitized mice com-pared to control group (p<0,05) including eosinophils. Our resultsconfirm an upper airway inflammation associated to an IgE-mediat-ed hypersensitivity reaction induced by the aeroallergen exposure.In addition, associated effects were demonstrated in the lungs, al-though more research needs to be done to clarify this upper-lowerairway interaction. The later could be helpful since AR and asthmarespond to similar treatment strategies.