Abstract:Objective To explore the effect of lycium barbarum polysaccharide on Th1/Th2 cytokines and eosinophil inflammation in nasal mucosa of allergic rhinitis (AR) rats by regulating Toll-like receptor 9/activated protein-1 (TLR9/AP-1) signaling pathway.Methods Sixty SPF male SD rats were randomly divided into normal (A) group, model (B) group, mometasone furoate (C) group, lycium barbarum polysaccharide (D) group, TLR9/AP-1 signaling pathway inhibitor (E) group and TLR9/AP-1 signaling pathway inhibitor combined lycium barbarum polysaccharide (F) group, with 10 rats in each group. AR model was established by ovalbumin sensitization method in all groups except group A. After successful establishment of AR model, one spray/side of mometasone furoate nasal spray was adopted intranasally in group C, 100 mg/kg lycium barbarum polysaccharide, 20 mg/kg AP-1 inhibitor SP100030, 20 mg/kg SP100030+100 mg/kg lycium barbarum polysaccharide were administered intragastrically in group D, E and F respectively. In groups A and B, normal saline of the same volume was administered intragastrically. The nasal symptoms were scored, and HE staining was used to detect the pathological morphology of nasal mucosa with eosinophils count. Serum levels Th1/Th2 of cytokines were detected by enzyme-linked immuno sorbent assay. The expression of TLR9/AP-1 signaling pathway-related proteins in nasal mucosa was detected by western blot.Results Compared with group A, the nasal symptom score, the number of eosinophils in nasal mucosa and the serum level of interleukin (IL)-4 in group B were significantly increased with decreased serum level of interferon (INF)-γ (all P<0.05). Compared with group B, the score of nasal symptoms, the number of eosinophils in nasal mucosa and the serum level of IL-4 in groups C and D were significantly decreased with increased serum level of INF-γ (all P<0.05), and the changes in group D were more significant than those in group C (all P<0.05). The structure of nasal mucosa from group A kept intact, while the epithelial structure of nasal mucosa from group B was disordered and incomplete with bleeding and infiltration of inflammatory cells such as eosinophils. Compared with group B, the pathological statuses of groups C and D were significantly improved with decreased eosinophils. The protein expressions of TLR9 and AP-1 in nasal mucosa tissues of group B were significantly higher than those of group A (both P<0.05), and their expressions in groups C and D were significantly decreased compared with group B (all P<0.05), and the changes in group D were more significant than those in group C (P<0.05). The differences between the protein expressions of TLR9 and AP-1 of group E and group D were statistically insignificant (both P>0.05), and the expressions in group F were significantly lower than those in group E (both P<0.05).Conclusion Lycium barbarum polysaccharide can effectively regulate Th1/Th2 cytokine level and relieve eosinophil inflammation in nasal mucosa in rats with AR, and the mechanism may be related to the inhibition of TLR9/AP-1 signaling pathway.
