Study On Protectve Effect Of Extract Of Dandelion On Acute Lung Injury Induced By Lipopolysaccharide In Mice

To study the protective effects of extract of dandelion on acute lung injury ( ALI) induced by lipopolysaccharide (LPS) and the molecular mechanism of protection in mice, to provide base for clinical prevention and treatment of acute pneumonia and lay the foundation for further development and utilization of dandelion as a gateway drug. First, aqueous extract of dandelion was prepared. Models of ALI were established by intranasal instillation of LPS, mice were randomly divided into control group, model group, dandelion (2.5,5,10 mg/kg) groups and dexamethasone (0.5 mg/kg) group. Pathological changes in lung tissues of mice were observed, lung dry weight and wet weight ratio, and myeloperoxidase (MPO) activity were detected, inflammatory cell counts and protein level in bronchoalveolar lavage fluid (BALF) were measured. TNF-a, IL-6, PGE2 were measured by ELISA method and NO was measured by Griess reagent. The mRNA expressions of iNOS and COX-2 were measured by RT-PCR. NF-κB (p65) protein expression was measured by Western blotting.Results:Models of ALI were established by intranasal instillation of LPS, pathological changes were obvious with the main features in ALI mice compared with the control group, and indicated that the building of model was successful. The different concentrations of aqueous extract of dandelion could decrease pathological changes of lung tissue in ALI mice compared with the model group. MPO activity of lung tissues significantlyreduced (P<0.01) ,, W/D, inflammatory cell counts and protein level, and TNF-a, IL-6, PGE2, NO levels were significantly inhibited (P<0.05 or P<0.01). The iNOS and COX-2 mRNA and NF-κB (p65) protein expressions of lung tissue were also significantly inhibited in ALI mice (P<0.05 or P<0.01)Conclusion:The extract of dandelion could decrease pathological changes of lung tissue in ALI mice, degree of pulmonary edema, MPO activity of lung tissues, inflammatory cell counts and protein level, TNF-a, IL-6, PGE2 and NO levels, inhibit iNOS and COX-2 mRNA expressions. It suggests that extract of dandelion has certain protective effect on ALI in mice, the protective mechanism may be completed through NF-κB pathway.