Abstract:
OBJECTIVE To study the effects of Pyrus sinkiangensis Yu. neutral polysaccharide(PSNP-1, PSNP-2) on ovalbumin(OVA)-induced acute allergic asthma in mice and its mechanism.
METHODS The 108 BALB/c mice were randomly divided into normal group, model group, dexamethasone positive group, PSNP-1 low, medium and high(10, 20, 40 mg·kg−1) dose groups, and PSNP-2 low, medium and high dose groups, with 12 mice in each group. A mixture of OVA(98%) and aluminum hydroxide was injected into the abdomen for sensitization. The 5% OVA solution was continuously atomized for 7 d, and the drug intervention lasted for 7 d. Bronchoalveolar lavage fluid was collected for ELISA, biochemical detection, HE, PAS and Masson staining. The mRNA expression levels of TLR4, NLRP3, IL-18, IL-1β, Caspase-1 and GSDMD in lung tissues were detected by qRT-PCR. The expression levels of NLRP3, Caspase-1, GSDMD, ASC, Nrf2, HO-1, NF-κBp65, IκBα in lung tissues were detected by immunohistochemical staining. The expression levels of NLRP3, Caspase-1, ASC and GSDMD-N in lung tissues were detected by Western blotting.
RESULTS Compared with the model group, PSNP-1 and PSNP-2 alleviated pathological changes such as inflammatory cell infiltration, mucus secretion, fibrosis and bronchial epithelial degeneration and hyperplasia in asthmatic mice, and significantly regulated the release levels of inflammatory cytokines and oxidizing factors. qRT-PCR results showed that, the mRNA expression levels of TLR4, NLRP3, IL-18, IL-1β, Caspase-1 and GSDMD were significantly decreased(P<0.05). Immunohistochemical results showed that NF-κB p65, NLRP3, Caspase-1, GSDMD, ASC were decreased(P<0.05), and the expression levels of IκBα, Nrf2, HO-1 were significantly increased(P<0.05). Western blotting results showed that the protein expression levels of NLRP3, Caspase-1, ASC and GSDMD-N were significantly decreased(P<0.05).
CONCLUSION PSNP-1 and PSNP-2 can effectively improve airway inflammation and oxidative stress in asthmatic mice, and the mechanism may be related to oxidative stress mediated by Nrf2 pathway and inflammatory immune damage regulated by NF-κB/NLRP3 pathway.