Paeonol Ameliorates Ovalbumin-Induced Asthma through the Inhibition of TLR4/NF-κB and MAPK Signaling

Asthma is a chronic inflammatory disease of the airways, with complex signaling pathways involved in its pathogenesis. It was reported that paeonol attenuated airway inflammation of ovalbumin (OVA)-induced mice. Therefore, it is of importance to further investigate the underlying mechanism. BALB/c mice were challenged with OVA for the asthma model, which was validated by the changed levels of IL-4, IFN-γ, and IgE. The elevation of IL-4 and the decreasing of IFN-γ were significantly in middle (p<0.05) or high (p<0.01) paeonol dose groups compared with OVA group. MIP-1β in bronchoalveolar lavage fluid (BALF) also decreased significantly in middle and high paeonol group compared with OVA group (p<0.01), which is similar to the change of its mRNA in lung tissues. Moreover, the inflammatory cells infiltration and collagen deposition were attenuated by paeonol and montelukast sodium via histology examination. At last the immune blot of the protein extracted from lung tissues demonstrated that paeonol decreased the expression of TLR4 and the nuclear translocation of NF-κB, as well as the phosphorylation levels of P38 and ERK in asthma model. In conclusion, paeonol ameliorated OVA-induced asthma through the TLR4/NF-κB and mitogen-activated protein kinase (MAPK) signaling.