Protective Effects of the Ethanol Extract of Viola tianshanica Maxim against Acute Lung Injury Induced by Lipopolysaccharides in Mice

Viola tianshanica Maxim, belonging to the Violaceae plant family, is traditionally used in Uighur medicine for treating pneumonia, headache, and fever. There is, however, a lack of basic understanding of its pharmacological activities. This study was designed to observe the effects of the ethanol extract (TSM) from Viola tianshanica Maxim on the inflammation response in acute lung injury (ALI) induced by LPS and the possible underlying mechanisms. We found that TSM (200 and 500 mg/kg) significantly decreased inflammatory cytokine production and the number of inflammatory cells, including macrophages and neutrophils, in bronchoalveolar lavage fluid. TSM also markedly inhibited the lung wet-to-dry ratio and alleviated pathological changes in lung tissues. In vitro, after TSM ($12.5-100{\mu}g/ml$) treatment to RAW 264.7 cells for 1 h, LPS ($1{\mu}g/ml$) was added and the cells were further incubated for 24 h. TSM dose-dependently inhibited the levels of proinflammatory cytokines, such as NO, $PGE_2$, $TNF-{\alpha}$, IL-6, and $IL-1{\beta}$, and remarkably decreased the protein and mRNA expression of $TNF-{\alpha}$ and IL-6 in LPS-stimulated RAW 264.7 cells. TSM also suppressed protein expression of $p-I{\kappa}Ba$ and p-ERK1/2 and blocked nuclear translocation of $NF-{\kappa}B$ p65. The results indicate that TSM exerts anti-inflammatory effects related with inhibition on $NF-{\kappa}B$ and MAPK (p-ERK1/2) signaling pathways. In conclusion, our data demonstrate that TSM might be a potential agent for the treatment of ALI.