Paeonol ameliorates lipopolysaccharides-induced acute lung injury by regulating TLR4/MyD88/ NF-κB signaling pathway.

: Paeonol has been found to hold analgesic, antipyretic and anti-allergic activities. Here, we investigated the protective effect of paeonol on acute lung injury (ALI) induced by lipopolysaccharides (LPS) and explored the underlying mechanisms on TLR4/MyD88/NF-κB signaling pathway. C57BL/6 mice were randomly divided into control (normal saline, NS, 0.2 mL/d), LPS (NS, 0.2 mL/d), LPS + dexamethasone (DXMS) (5 mg/kg/d), LPS + paeonol (50, 25, 12.5 mg/kg/d) groups. The results of the lung tissue scores scale and HE staining showed that paeonol could attenuate the infiltration of inflammatory cells and the thickening of alveolar wall significantly. The result of W/D ratio showed that paeonol could also prevent pulmonary edema, as well as inhibit significantly the levels of TNF-α, IL-1β and IL-6 in serum and proteins expression and mRNA. In addition, paeonol can also downregulate the expression or phosphorylation of TLR4, MyD88 and NF-κB. In general, our findings showed that the protective effect of paeonol on LPS-induced ALI by regulating TLR4/MyD88/NF-κB signaling pathway. This study provides evidence for the application of paeonol in treating ALI.