ABSTRACT
ObjectiveTo investigate the therapeutic effect of Xiao Qinglongtang （XQLT） on ovalbumin （OVA）-induced allergic rhinitis （AR） in mice and its effect on the interleukin-33 （IL-33）/suppression of tumorigenicity 2 （ST2） signaling pathway. MethodSeventy-two female BALB/c mice of SPF grade were randomly divided into a control group， a model group， a positive control group （loratadine， 2.05 mg·kg-1）， and low-， medium-， and high-dose （5.005，10.01，20.02 g·kg-1） XQLT groups. All mice except for those in the control group were sensitized by intraperitoneal injection of OVA solution， and the AR model was induced by intranasal drops of OVA solution. Thirty minutes before local intranasal drops， drugs were administered once， and mice in the control group and the model group received phosphate buffered saline （PBS） at 20 mL·kg-1 for 7 days. After the last intranasal drop of OVA solution， the times of sneezing and nasal rubbing of mice within 10 min was recorded. After drug administration for 7 days， blood samples were collected， and nasal bones of mice were decalcified for the preparation of pathological sections. The content of OVA-specific immunoglobulin E （OVA-sIgE）， interleukin-4 （IL-4）， interleukin-5 （IL-5）， and interleukin-13 （IL-13） was detected by enzyme-linked immunosorbent assay （ELISA） kits. Hematoxylin-eosin （HE） staining， periodic acid-Schiff （PAS） staining， and Giemsa staining were used to observe the pathological changes， goblet cell hyperplasia， and eosinophil infiltration of nasal mucosa， respectively. Western blot was used to detect the expression levels of IL-33， ST2， and IL-1 receptor accessory protein （IL-1RAP） in nasal mucosa. ResultCompared with the control group， the model group showed increased times of sneezing and nasal rubbing （P<0.01）， edema and thickening of nasal mucosa， goblet cell hyperplasia and eosinophil infiltration， increased serum levels of OVA-sIgE， IL-4， IL-5 and IL-13 （P<0.01）， and increased protein expression of IL-33， ST2， and IL-1RAP in nasal mucosa （P<0.05，P<0.01）. After drug administration， compared with the model group， the high-dose XQLT group showed reduced times of sneezing and nasal rubbing （P<0.01）， improved pathological conditions of nasal mucosa， reduced serum levels of OVA-sIgE， IL-4， IL-5， and IL-13 （P<0.01）， and declining protein expression of IL-33， ST2， and IL-1RAP in nasal mucosa （P<0.05，P<0.01）. ConclusionXQLT has a therapeutic effect on OVA-sensitized AR mice， and the mechanism may be related to the regulation of the IL-33/ST2 signaling pathway and Th2 inflammatory cytokine to reduce Th2 inflammatory response and alleviate nasal mucosal injury.