The Role Of CD18 Adhesion Molecule In Rats With Acute Lung Injury And The Study About Intervention Of Tanshinoneâ…¡A

Objective to study the role of CD18 adhesion molecule in rats withAcute Lung Injury ,to research the intervention of tanshinoneⅡAand its possible mechanism 。Methods LPS(lipopolysaccharide O111:B4)was injected intravenouslyto form ALI model.Thirty-two healthy Sprague-Dawley rats wasrandomly divided into 4 groups(each group has 8 rats,male andfemale in half):1)ALI group:LPS(5mg/kg) was given by intravenouslyinjection ,PEG400(4ml/kg) was given from abdominal cavity beforethat about 30 minutes.2)control group :LPS was replaced by normalsaline,the others are the same as that used in ALI.3)TanⅡApretreatment group:LPS was given by intravenously injection,TanⅡA(6mg/kg) was given from abdominal cavity before that about 30minutes.4)TanⅡA interference group: LPS was given in vein ,thenan hour later, TanⅡA (6mg/kg) was given from abdominal cavity.Allthe animals were abserved about 6 hours after the injection ofLPS/normal saline. 2ml anti-coagulation venuous blood was used toinvestigate the changes of coagulation using CA-1500 auto-blood-analysis machine.Another 0.2ml anti-coagulation venous blood wasused to investigate the PMN-CD18 expression.The PMN was identifiedaccording to its character,then its mean fluorescence channel(MFC)was abtained.The intensity of MFC represents the density of CD18 onPMN.1ml arteral blood from carotid was used for blood gasanalysis.The animals were sacrificed at the end of experiment bybleeding.The whole lung was taken out from the thorax,the blood onits surface was sucked in filter paper.The left lung was used forwet and dry weigh ratio(W/D) after it has been baked in the dry upmachine about 80℃for 24 hours.The right upper lung tissue wasmade into slices(hematoxylin-eosin dying).Then ,we can analysisthe slices in quantity and quality using pathologic stereology andimage analysis to count the PMN recruitment number in the lungsepta,to measure the mean width of the alveolar septa,the alveolarvolume density and alveolar surface density.The lung tissue takenfrom the middle lobar of right lung was made into lung tissueliquid for the measurement of MDA(malondialdehyde) using themethod called TBA.Results 1. observation of the whole animal:The rats in ALI groupbecame dyspneic and tachypneic about 110 perminute.The rats in TanⅡA pretreatment and interference groups have less dyspnea andbreathing rate compared with ALI group.The rats in control grouphave no dyspnea and normal movement.2.observation of lungtissue:the lung of ALI group on the whole is bigger in volume ,its colour is pink or dark red,pink liquid can be seen from itssection.The lung of TanIIA pretreatment and interference groupshave no obvious enlargement in volume .Its colour is pale. Fromthe observation under light microscope,we can see that theinteralveolar septa in the lung of ALI group is swollen and wider,having more PMN recruitment.There are also many un-openedalveolars.The lung in control group is normal,its alveolar issmooth having complete structure ,its interalveolar septa is thinand has less PMN recruitment.The lung in TanIIA pretreatment andinterference groups have less impairment and disappearence ofalveolar.Their alveolar septa are thinner than that of ALI havingless PMN recruitment.3.Compared with control group, the expressionof PMN-CD18 ,MDA content(P<0.01),wet/dry ratio(P<0.05),hypercoagulation state and acidosis are increased obviously inthe ALI group.From the lung slice we can see that PMN recruitmentin the lung is higher;the width of alveolar septa is wider;thealveolar volume density(VV) and alveolar surface density (SV)are lower( P<0.01).4.Compared with ALI group,the expression ofPMN-CD18 is lower in TanshenoneⅡA pretreatment group(P<0.01)andinterference group(P<0.05).It also has lessened MDA content andW/D ratio(P<0.05) and ameliorated coagulation abnormality andacidosis(P<0.01).From the lung slice,we can find that in thesetwo groups ,the PMN recruiment and the width of alveolar septa aredecreased (P<0.01);the alveolar volume density (VV )(P<0.05)and alveolar surface density(SV)(P<0.01) are increased 5.Fromcorrelation analysis, PMN-CD18 expression is negative correlatedwith the VV(r =-0.785,P<0.01) and SV ( r =-0.955, P<0.01);positivecorrelated with the width of alveolar septa of the lung(r=0.97,P<0.01);PMN recruitment is negative correlated with the VV(r =-0.876,P<0.01)and SV ( r =-0.994 P<0.01), positive correlatedwith the width of alveolar septa of the lung (r=0.954,P<0.01);PMN-CD18 expression is positive correlated with PMNrecruitment in the lung ( r=0.969,P<0.01).Conclusions Acute Lung Injury has hypercoagulation,increasedexpression of CD18 on PMN.It also has more PMN recruitment andlipid peroxidation in lung tissue.Its lung edema is very heavy.Theexperiment show that the recruitment of PMN is the importantfactor in causing ALI.The increased CD18 expression on PMN plays animportant effect in this course and has a positive correlationwith the injury extent of the lung.TanshinoneⅡA plays itsprotective role in ALI through ameliorating the hypercoagulation,decreasing PMN-CD18 expression,decreasing PMN recruitment andlessening the extent of lipid peroxidation.