Effect of baicalin on alveolar fluid clearance in rats with acute lung injury

Abstract:

Objective：To research the effect of baicalin on alveolar fluid clearance（AFC） in rats with acute lung injury（ALI） induced by lipopolysaccharides（LPS）. Methods：Sprague-Dawley（SD） rats were randomly divided into control group，ALI group and baicalin pretreatment group（ALI+baicalin group），with 5 rats in each group. The ALI+baicalin group was further divided into three subgroups with different concentrations（10，50，100 mg/kg）. SD rats in each group were killed for measurement of ratio of wet to dry（W/D） weight of lung tissue，cyclic adenosine monophosphate（cAMP） level by radioimmunoassay，pathological changes and AFC at 2，4 and 6 h. Results：Compared with ALI group[W/D weight：（9.88±1.53）；concentration of cAMP：（265.80±62.39） pmol/g]，baicalin pre-treatment[baicalin 10 mg/kg group：（7.94±1.14）；baicalin 50 mg/kg group：（6.13±1.34）；baicalin 100 mg/kg group：（5.38±1.43）] significantly decreased W/D weight of lung tissue（P＜0.05），and [baicalin 10 mg/kg group：（381.00±60.51） pmol/g；baicalin 50 mg/kg group：（493.40±63.93） pmol/g；baicalin 100 mg/kg group：（582.40±47.44） pmol/g] significantly increased concentration of cAMP in lung tissue（P＜0.05） in a dose-dependent manner with increasing doses. Interstitial edema and inflammatory cell infiltration were markedly decreased when being pretreated with baicalin. AFC was significantly increased in ALI+baicalin group in a dose-dependent manner at different intervals（P＜0.05）. Meanwhile，cAMP concentration in lung tissue was positive correlated with AFC（r=0.984，P=0.002）. Addition of amiloride to the instillate decreased fluid clearance significantly. Baicalin or LPS had no significant effect on AFC in rats with ALI as amiloride being added in the instillate（P＞0.05）. Conclusion：Baicalin alleviates low AFC in rats with ALI probably by increasing intercellular cAMP level to modulate epithelial sodium channel.