Effects Of Ambroxol On The Expression Of SP-A And MPO In Lung Of Rats With Mechanical Ventilation

ObjectiveTo explore the effects of ambroxol on ventilator induced lung injury(VILI) by analying thechanges of surfactant protein A (SP-A) and myeloperoxidase(MPO) in lung of rats withmechanical ventilation．MethodsTwenty-four healthy male Wistar rats were randomly divided into there groups:controlgroup,mechanical ventilation group(MV group) and ambroxol pretreatment group(AMBgroup)．The pathological changes of the lungs and the neutrophil counts in bronchoalveolarlavage fluid(BALF) were detected,the protein level in BALF was measured by brillant bluemethod．MPO activity in pulmonary tissues and BALF was determined by Myloperoxidaseactivity assay,the expression of SP-A mRNA and its protein in pulmonary tissues weredetermined by reverse transcription-polymerase chain reaction (RT-PCR) andimmunohistochemistry staining．Results1. Pathologic alterations under light microscope:In the control group,the structure ofalveolar and the epithelium of bronchioles were intact,the alveolar walls were normal withoutany inflammatory cells infiltration．However,in the MV group,there were masive inflammatorycells infiltration,the alveolar walls were thickened,parts of the alveolar walls were ruptured andfused and the alveolar hemorrhage were observed．Of the AMB group there were a littleinflammatory cells infiltration,the degree of interstitial edema were alleviatived compared withthe MV group．2. Compared with control group and AMB group,the protein level,the neutrophil counts,the MPO activity in BALF and the MPO activity in lung were obviously increased in MV group(all P<0.01)；There was no statistical significance between AMB and control group on theseindicators (P >0.05)．3. Compared with control group and AMB group,the expression of SP-A mRNA and itsprotein in lung were decreased(all P<0.01)；There was no statistical significance between AMBand control group on these indicators (P >0.05)．4. Making correlation analysis between the expression of SP-A and MPO activity,itindicates that there is negative correlation between the expression of SP-A and the MPOactivity(r= -0.775,P＜0.05)． ConclusioConclusion1. Compared with control group,the neutrophil counts,MPO activity in lung of rats wereobviously increased and the expression of SP-A mRNA and its protein in lung of rats wereobviously decreased in high tidal volume ventilation group．And the expression of SP-A wascorrelated with the MPO activity negatively．The decreased of SP-A mRNA and its protein werecaused by the activated neutrophil directly or indirectly in high tidal volume ventilation,whichplays a important role in the development of VILI．2. Ambroxol may have protective effects on VILI by inhabitting the activation ofneutrophil,decreasing the MPO activity and increasing the expression of SP-A mRNA and itsprotein in lung of rats with mechanical ventilation．...