The protective effects of bilirubin with different doses against LPS-induced acute lung injury in rats

Objective To investigate the effects of bilirubin with different doses on LPS-induced acute lung injury(ALI) in rats and its possible mechanism.Methods Forty male Wistar rats(200～250 g) were randomly divided into four groups: the control group,the ALI model group,the low dose and the high dose pre-treatment bilirubin group.Histopathological examination,biological markers for the lung specimens and oxidative/antioxidative parameters in the homogenate of the rat lungs were determined.Results ①The ALI model group,the biological markers of ALI including lung index(LI),the contents of total protein,cell counts and neutrophil percent age in bronchoalveolar lavage fluid(BALF),lung permeability index(LPI) significantly increased compared with the control group(P0.01).Pathologic changes decreased.The content of MDA in the homogenate of the lung tissues were significantly high(P0.01),however the level of superoxide dismutase(SOD) and glutathione peroxidase(GSH-Px) were decreased(P0.01).②Two pretreatments with bilirubin inhibited the LPS-induced changes in lung injury parameters,but there were distinctions between two groups.Conclusion Bilirubin might significantly alleviate the degree of ALI by antioxidation.These effects were concerned with the different doses of bilirubin.