Study On Notch Signaling Pathway In Rat Lung Tissue With Acute Lung Injury

Objective： This study used acute lung injury rats stimulated withlipopolysaccharide(LPS) as the research object, to observe changes of the expressionvariability of Notch1in rat lung tissue during the specific inhibitor DPAT inhibitingNotch signal from beginning to end, then explore the function of Notch signalingpathway in acute lung injury.Methods：Thirty-two pathogen-free Sprague Dawley rats weighing from300g to500g were randomly divided into four groups(n=8each), including control group,acute lung injury group, intervention group and interference group. The animalmodel was induced by intratracheal instillation of LPS, rats in intervention groupreceived the inhibitor DAPT by intratracheal instillation after one hour LPS wasinstilled into tracheas of rats, rats in control group received nothing intratracheallywhile rats in solvention group received DMSO intratracheally.4hours later, rats weresacrificed and isolated lung while closed the trachea. Artery blood gas, lung tissuehistological changes assessed by HE staining and lung tissue wet／dry ration wereobserved, lung tissues were collected and subjected for immunohistochemistryanalysis to evaluate the expression patterns of Notch1protein. Use SPSS19.0statistical software to do the statistical analysis, also use t-test to compare the averagevalue of two samples and applying one-factor analysis of variance to multi-samplecomparisons and having LSD-t test for inter-groups comparisons.Results：Control group rats lung tissue structure were clear, alveolar were intact at alltime, LPS treated rats lung tissue structure showed obvious haemorrhage, effusion,alveolar septal thickeness and transparent blot formation, as compared with controlgroup rats (P<0.01). The injury of lung tissue structure in DAPT+LPS group weresignificantly lighter than in ALI group (P<0.01). but significantly heavier than incontrol group (P<0.01). In LPS treated rats group the grade of the pathology and lungW/D weight ratio showed obvious increasing, as compared with control group rats (P<0.01), The grade of the pathology and moisture content in DAPT+LPS group weresignificantly lower than in ALI group (P<0.01). but significantly higher than incontrol group (P<0.01). To compare with control group rats, Notch1expression wassignificantly increased in lung tissues of LPS treated rats (P<0.01), as evidenced byimmunohistochemistry. The expression of Notch1protein in DAPT+LPS group weresignificantly lower than in ALI group (P<0.01). but significantly higher than incontrol group (P<0.01). Solvention group rats in lung tissue histological changes,grade of the pathology, lung W/D weight ratio and expression of Notch1protein is aswell as control group rats (P>0.01).Conclusions：LPS caused amount of expression of Notch1protein in lung tissue,after inhibiting Notch signal, the injury of lung tissue were decreased, whichsuggested that Notch signaling pathway involves in control of inflammation and mayplay an important role in ALI.