Abstract:

Objective   To elucidate the expression and efficacy of CD4+CD25+FOXP3+ regulatory T cells(Tregs)as well as IgE, IL-4 and IL-5 in a stable experimental allergic rhinitis (AR) mouse model and in administration of nasal corticosteroid. Methods   Female Balb/c mice of 4-5 weeks were randomly divided into three groups: the normal group, the AR group and the nasal corticosteroid treatment group (n=10). The normal group was without any intervention; The AR group was sensitized by intraperitoneal injection and then challenged by atomization and intranasal instillation of ovalbumin (OVA) to induce allergic airway inflammation; The nasal corticosteroid treatment group was administrated by aerosol inhalation of fluticasone propionate for 10min after mice were successfully challenged. After 24h of the final challenge, all mice were sacrificed to collect samples. Nasal mucosa was stained with HemateinEosin (HE). Flow cytometry was applied for analyzing number of Tregs in paratracheal draining lymph nodes and the spleen. ELISA was used to assay serum OVA-specific IgE, IL-4 and IL-5 levels in nasal lavage fluid. Results   Compared to the normal group, mice in the AR group exhibited a significantly increased number of eosinophils in nasal mucosa, up-regulated expression of Tregs in paratracheal draining lymph nodes, and elevated OVA-specific IgE levels in serum and IL-4 and IL-5 levels in NALF. However, mice administrated with nasal corticosteroid were detected more significantly up-regulated Tregs in both paratracheal draining lymph nodes and the spleen, along with significantly decreased IgE, IL-4 and IL-5 levels. Conclusion   Tregs not only play an immunomodulatory role in the development of AR mediated by IgE， IL-4 and IL-5, but also in the administration of nasal corticosteroid.