Mahuang Xixin Fuzi decoction protects against ovalbumin-induced allergic rhinitis by inhibiting type 2 innate lymphoid cells in mice

Abstract

Objective: As a traditional herbal formula, Mahuang Xixin Fuzi decoction (MXFD) has been used to treat allergic rhinitis (AR). It regulates the transcription factor GATA3 in T cells, blocks Th2 skewing and rebalances the Th1/Th2 immunity. Type 2 innate lymphoid cells (ILC2s) are closely associated with GATA3. However, it remains unknown whether ILC2s could be one mechanism through which MXFD acts. We sought to elucidate the efficacy and mechanism of action of this decoction in AR treatment. Methods: Forty C57BL/6J female mice were equally divided into control, model, loratadine- and MXFD-treated groups in random. AR was induced by ovalbumin (OVA), and then treatment with loratadine or MXFD was administered. AR scores were evaluated and compared before and after treatment. Pathological changes in the nasal mucosa and lung were observed using hematoxylin-eosin staining of tissue samples. Activation of ILC2 in nasal mucosa was assessed by immunofluorescence and quantitative polymerase chain reaction analysis. ILC2 cell count in lungs was measured by flow cytometry and levels of interleukin- (IL) 4, IL-5 and IL-13 in serum were detected by ELISA. Results: The decoction alleviated the symptoms of AR in mice, improved vascular congestion and expansion, glandular hyperplasia and inflammatory cell infiltration in mouse nasal mucosa and slowly improved the interstitial pneumonia and lesions. Meanwhile, MXFD reduced the number and percentage of ILC2s in the nasal mucosa and lungs, downregulated the expression of GATA3 mRNA and RORα mRNA, and reduced the related inflammatory cytokine levels, including IL-4, IL-5 and IL-13. Conclusion: These data suggest that inhibition of ILC2s by MXFD may be an important means by which to treat AR. Keywords: Mahuang Xixin Fuzi decoction, Allergic rhinitis, Type 2 innate lymphoid cells