Oleanolic acid regulates Treg/Th17 cell imbalance in allergic rhinitis by inhibiting autophagy
Objective:To explore effect of oleanolic acid on allergic rhinitis(AR)and its potential mechanism.Methods:Peripheral blood mononuclear cells(PBMCs)were isolated by density gradient centrifugation.Real-time quantitative PCR was used to detect expressions of Foxp3,IL-17A,Beclin1,and RORγt mRNA in nasal mucosa;flow cytometry was employed to assess proportion of Treg and Th17 cells in PBMCs;Western blot was utilized to determine expressions of RORγt,LC3-Ⅰ,LC3-Ⅱ,Beclin1,and P62 proteins in nasal mucosal.Mice were randomly divided into Control,ovalbumin(OVA),L-oleanolic acid,H-oleanolic acid,DSGC,3-MA and H-oleanolic acid+Rapa groups.Histological changes were observed by HE staining and Periodate Schiff(PAS)staining.Serological changes,expressions of IL-17A,IL-10,eosinophilic cationic protein(ECP)and anti-OVA-specific antibodies were detected by ELISA.Results:AR patients had Th17/Treg imbalance and activated autophagy.Oleanolic acid restored Th17/Treg balance and inhibited autophagy in vitro.In vivo experiments demonstrated that oleanolic acid inhibited OVA-induced allergic nasal symptoms and activation of autophagy pathway,which was same as regulation of 3-MA,while Rapa could weaken effects of high dose of oleanolic acid.Moreover,oleanolic acid reduced infiltration of different inflammatory cells of nasal lavage fluid,prevented damages to epithelial cells,and improved nasal mucosal thickness and mucus secretion.Oleanolic acid regulated balance of mouse Th17/Treg-associated cytokines expressions.Conclusion:Oleanolic acid can be used to treat AR,whose effect is realized through inhibiting autophagy to regulate Th17/Treg balance.