Epithelial to ... · intheperitonealfibrosismodelgroup,αSMAex ...

10
中南大学学报(医学版) JCentSouthUniv MedSci 2011 36 http //xbyx.xysm.net Dateofreception 2010-07-24 Biography DUANShaobin Ph.D. professor mainlyengagedintheresearchofchronickidneydisease acutekidneyinjury andperitoneal dialysis. Correspondingauthor YUJie Email Duansb528@hotmail.com Foundationitem ThisworkwassupportedbytheDepartmentofScienceandTechnologyofHunanProvince P.R.China 2008JT3005 Epithelialtomesenchymaltransdifferentiationofperitonealmesothelial cellsmediatedbyoxidativestressinperitonealfibrosisrats DUANShaobin YUJie LIUQing WANGYuhui PANPeng XIAOLi LINGGuanghui LIUFuyou .DepartmentofNephrology SecondXiangyaHospital CentralSouthUniversity InstituteofNephrology CentralSouthUniversity CentreofKidneyDiseaseandDialysisinHunanProvince Changsha 410011 .People sHospitalofAnyang AnyangHenan 455000 China Abstract Objective Toinvestigatetheroleofoxidativestressintheepithelialtomesenchy maltransdifferentiation EMT ofperitonealmesothelialcellsinratmodelofperitonealfibrosisand theeffectofprobucolonperitonealfibrosis.Methods Theratmodelofperitonealfibrosiswasin ducedby4.25%highglucoseperitonealdialysisfluid PDF .Theratswererandomlydividedinto 4groups thecontrolgroup thesalinegroup theperitonealfibrosisgroup andtheprobucolgroup. A4hourperitonealequilibrationtest PET wasperformed4weekslater.Theperitonealfunction andnetultrafiltrationUF volumeweredetermined.ThelevelofmalondialdehydeMDA and glutathioneperoxidaseGSHPx inperitonealtissuewereexamined.Thehistologyofperitoneal membranewasevaluatedbylightmicroscopy.Ecadherinand α smoothmuscleactin α SMA pro teinexpressionwasevaluatedbyimmunohistochemicalmethodandWesternblot. Results Themes othelialcellsweredetachedfromperitonealmembraneinperitonealfirbosisrats.Comparingwiththe controlrats thethicknessofvisceralperitoneum thelevelofMDA andtheSMAproteinexpression wereincreasedwhilethenetultrafiltrationvolume thelevelofGSHPxandEcadherinproteinex pressionweredecreasedinperitonealfirbosisrats.Allthesechangeswerereversedintheratstreated withprobucol. Conclusion Oxidativestressplaysanimportantroleintransdifferentiationofperito nealmesothelialcellintheperitonealfibrosisrats.Probucolcanimprovestructureandfunctionof peritoneum andpartiallyreversetheEMTbyreducingtheoxidativestress. Keywords peritonealdialysis peritonealfibrosis peritonealmesothelialcell transdiffer entiation oxidativestress probucol

Transcript of Epithelial to ... · intheperitonealfibrosismodelgroup,αSMAex ...

Page 1: Epithelial to ... · intheperitonealfibrosismodelgroup,αSMAex ...

中南大学学报(医学版)

JCentSouthUniv(MedSci) 2011,36(1)  http://xbyx.xysm.net

Dateofreception 2010-07-24

Biography DUANShaobin,Ph.D.,professor,mainlyengagedintheresearchofchronickidneydisease,acutekidneyinjury,andperitoneal

dialysis.

Correspondingauthor YUJie,Email:Duansb528@hotmail.com

Foundationitem ThisworkwassupportedbytheDepartmentofScienceandTechnologyofHunanProvince,P.R.China(2008JT3005).

Epithelialtomesenchymaltransdifferentiationofperitonealmesothelialcellsmediatedbyoxidativestressinperitonealfibrosisrats

DUANShaobin1,YUJie2,LIUQing1,WANGYuhui1,PANPeng1,XIAOLi1,LINGGuanghui1,LIUFuyou1

(1.DepartmentofNephrology,SecondXiangyaHospital,CentralSouthUniversity;InstituteofNephrology,

CentralSouthUniversity;CentreofKidneyDiseaseandDialysisinHunanProvince,Changsha410011;

2.People’sHospitalofAnyang,AnyangHenan455000,China)

Abstract: Objective Toinvestigatetheroleofoxidativestressintheepithelialtomesenchy

maltransdifferentiation(EMT)ofperitonealmesothelialcellsinratmodelofperitonealfibrosisand

theeffectofprobucolonperitonealfibrosis.Methods Theratmodelofperitonealfibrosiswasin

ducedby4.25% highglucoseperitonealdialysisfluid(PDF).Theratswererandomlydividedinto

4groups:thecontrolgroup,thesalinegroup,theperitonealfibrosisgroup,andtheprobucolgroup.

A4hourperitonealequilibrationtest(PET)wasperformed4weekslater.Theperitonealfunction

andnetultrafiltration(UF)volumeweredetermined.Thelevelofmalondialdehyde(MDA)and

glutathioneperoxidase(GSHPx)inperitonealtissuewereexamined.Thehistologyofperitoneal

membranewasevaluatedbylightmicroscopy.Ecadherinandαsmoothmuscleactin(αSMA)pro

teinexpressionwasevaluatedbyimmunohistochemicalmethodandWesternblot.Results Themes

othelialcellsweredetachedfromperitonealmembraneinperitonealfirbosisrats.Comparingwiththe

controlrats,thethicknessofvisceralperitoneum,thelevelofMDA,andtheSMAproteinexpression

wereincreasedwhilethenetultrafiltrationvolume,thelevelofGSHPxandEcadherinproteinex

pressionweredecreasedinperitonealfirbosisrats.Allthesechangeswerereversedintheratstreated

withprobucol.Conclusion Oxidativestressplaysanimportantroleintransdifferentiationofperito

nealmesothelialcellintheperitonealfibrosisrats.Probucolcanimprovestructureandfunctionof

peritoneum,andpartiallyreversetheEMTbyreducingtheoxidativestress.

Keywords:  peritonealdialysis; peritonealfibrosis; peritonealmesothelialcell; transdiffer

entiation; oxidativestress; probucol

43

Page 2: Epithelial to ... · intheperitonealfibrosismodelgroup,αSMAex ...

EMTofperitonealmesothelialcellsmediatedbyoxidativestressinperitonealfibrosisrats DUANShaobin,etal.

氧化应激在腹膜纤维化大鼠模型

腹膜间皮细胞转分化中的作用

段绍斌1,于洁2,刘庆1,王予慧1,潘鹏1,肖力1,凌光辉1,刘伏友1

(1.中南大学湘雅二医院肾内科,中南大学肾病研究所,肾脏疾病与血液净化学

湖南省重点实验室,长沙 410011;2.河南省安阳市人民医院,河南 安阳 455000)

[摘要] 目的:研究氧化应激在腹膜纤维化大鼠腹膜间皮细胞转分化中的作用;观察抗氧化剂普罗

布考的干预效应。方法:采用 4.25%高糖腹透液以 100mL/kg腹腔注射法复制腹膜纤维化大鼠模型,

实验分为正常对照组、生理盐水对照组、腹膜纤维化模型组和普罗布考干预组。4周后行腹膜平衡试

验,处死大鼠,准确测量超滤量,检测腹膜功能;取肠系膜组织匀浆后测定氧化应激指标丙二醛(MDA)

和谷胱甘肽过氧化物酶(GSHPx)含量;留取壁层腹膜组织行 HE及 Masson染色,并测量腹膜厚度;采用

免疫组织化学和 Western印迹检测大鼠壁层腹膜组织腹膜间皮细胞转分化指标 Ecadherin蛋白和 α平

滑肌肌动蛋白(SMA)的表达。结果:腹膜纤维化模型组大鼠腹膜间皮细胞脱落,与正常对照组比较,壁

层腹膜厚度和肠系膜匀浆 MDA含量增加(P<0.01),腹腔超滤量和 GSHPx活性降低(P<0.01);转分

化指标 αSMA蛋白表达明显上调(P<0.01),Ecadherin蛋白显著下调(P<0.01)。普罗布考干预组

间皮细胞基本完好,与纤维化模型组比较,壁层腹膜厚度和肠系膜匀浆 MDA含量降低(P<0.01),腹腔

超滤量(P<0.05)和 GSHPx活性(P<0.01)上升;腹膜 αSMA蛋白表达明显下调(P<0.01),Ecad

herin蛋白表达明显上调(P<0.01)。结论:氧化应激在高糖腹透液诱导的大鼠腹膜间皮细胞转分化中

起一定作用;普罗布考可改善腹膜纤维化大鼠模型腹膜结构和功能,部分逆转腹膜间皮细胞转分化。

[关键词]  腹膜透析; 腹膜纤维化; 腹膜间皮细胞; 转分化; 氧化应激; 普罗布考

DOI:10.3969/j.issn.16727347.2011.01.006

  Peritonealdialysis(PD)isoneoftheeffectivemethodsfortheendstagerenaldisease(ESRD),whichwasassociatedwithimprovedsurvivalcomparedwithhemodialysisamongsubgroupswithage<65years,nocardiovasculardisease.UltrafiltrationfailurecausedbyperitonealfibrosisisthemainreasonforpatientstowithdrawPD[12].Peritonealmesothelialcellsarethelargestcellgroupintheabdomen.Longtermnonphysiologicalperitonealdialysisfluid(PDF)willcausedamagestotheperitonealmesothelialcells,suchasexpansionofintercellularjunction,reductionordisappearanceofmicrovilli,increaseofglucosecarrierinmembrane,disorderoftheexpressionofcytokinesanddisappearanceofcellphenotype,whichwillresultinepithelialmesenchymaltransdifferentiation(EMT),dysfunctionofdefension,structuralchangeoftheabdomen,ultrafiltrationfailure,anddecreasedefficiencyofPD.EMTisthekeypathologicalchangeofperitonealfibrosisin

theearlystage,andisreversible[34].

Researches[57] showedthatoxidativestresswas

foundinPD patients,andreactiveoxygenspecies

(ROS)wereproducedthroughvariousways;high

concentrationglucosewillcauseoxidativestressin

theperitonealmesothelialcellsandenhancethefi

brosisofperitoneum.Probucolisoneofthebestan

tioxidant,whichservestoantioxidant,reducepro

teinuria,antifibrosis,and antiinflammation[89].

Butithasnotbeenreportedwhetherthatprobucol

partiallyreversesEMTtoprotectperitoneum byan

tioxidation.Inthisexperiment,weestablishedperi

tonealfibrosismodel[10]byusinghighglucosedialy

sate,studiedtheroleofoxidativestressplayedin

thetransdifferentiationofperitonealmesothelialcells,

anddeterminedtheprotectionofprobucoltotheperi

toneuminperitonealfibrosismodelratsandtherele

vantmechanisms,soastoprovidenewmethodsfor

preventionandtreatingofperitonealfibrosis.

53

Page 3: Epithelial to ... · intheperitonealfibrosismodelgroup,αSMAex ...

中南大学学报(医学版),2011,36(1)  http://xbyx.xysm.net

1  MATERIALSANDMETHODS

1.1 ReagentsDianealperitonealdialysate(4.25%)wasfrom

BaxterCompany(USA);probucolwasfromBeijingChengdePharmaceuticalGroupCo.,Ltd.(China);rabbitantiratEcadherinpolyclonalantibodywasfrom SantaCruzBiotechnology(USA);rabbitantiratαsmoothmuscleactin(SMA)polyclonalantibodywasfromBeijingBiosynthesisBiotechnologyCo.,Ltd.(China);secondaryantibodykitofimmunohistochemistrywasfrom ShenzhenJingmeiBiotechnologyCo.,Ltd.(China);BCAproteinconcentrationdeterminingkitwasfrom BiotechnologyJiangsuNantongBiyuntianInstitute(China);malondialdehyde(MDA) kitandGSHPxkitwerefrom Nanjing Jiancheng Bioengineering Institute(China).1.2 Establishmentofanimalmodels

Atotalof24healthymaleSDrats(provided by Beijing Weitonglihua Laboratory AnimalTechnologyCo.,Ltd)weighing180-220gwasdividedintothenormalcontrolgroup,thesalinecontrolgroup,theperitonealfibrosismodelgroup,andtheprobucolinterventiongroup,6ratsineachgroup.Modelofperitonealfibrosiswasmadewiththemethodestablishedbyourlaboratory.Theratswerefedwithstandardratfeedexceptthoseintheprobucolinterventiongroupwhosefeedwereaddedwith1% probucol.Thetemperatureofthefeedingroom werekeptat18-22 ℃.Nointerventionwasdonetothenormalcontrolgroup;ratsinthesalinecontrolgroupwereinjectedwithsalineintheabdomenat100mL/kgonceaday;ratsintheperitonealfibrosismodelgroup and probucolinterventiongroupwereinjectedwith4.25% peritonealdialysateintheabdomenat100mL/kgonceaday;andalltheratswereweighedonthemorningofthe1st,8th,15th,22nd, and30th daywhentheirstomachswereempty.

1.3  Peritonealfunctiontestandcollectionofsample

Fortyeighthoursafterintraperitonealinjection,allratswereanesthetizedbyintraperitonealinjectionof10% chloralhydrate(3mL/kg).Peritonealdialysateof4.25% wasperfusedandkeptinthebodyofratsfor4h.Dialysate(0.5mL)wascollectedat0and4haftertheperfusion,respectively.Theabdominalcavitiesoftheratswereopened,thebodyfluidwasabsorbedwithgauzeandweighed.Thebodyfluidvolumewascalculated.Thebloodsampleswerecollectedthroughinferiorvenacava.Parietalperitonealtissuesfrom upperabdomenwerefixedwith10% neutralformalin.2-4cm2omentummajuswascutfromthe5cmlowerpartofthepylorus.Theindexofperitonealfunctionwascalculatedbasedonthefollowingformula:pureultrafiltrationvolume= bodyfluidvolume-25mL.Automaticbiochemistryanalyzerwasusedtomeasurethecreatinineconcentrationofthedialysate(D),glucoseconcentrationofthedialysate(D4),glucoseconcentrationoftheoriginaldialysate(D0),andcreatinineconcentrationofthebloodserum (PCr).ThevaluesofD/PCr andD4/D0 werecalculated.Masstransferglucose(MTG)werecalculatedbasedontheformula:MTG =(D0×25-D4×bodyfluidvolume)/bodyweight.1.4  MeasurementoftheMDA contentandGSHPxactivity

Atatalof0.2gomentum majustissueswasweighout,andmadeinto10% homogenateintheproportionof1∶9(w∶v).Thehomogenatewascentrifugedat2000r/minfor10min.Thesupernatantwasretained,andkeptin-70℃ refrigerator.Theproteincontent,MDA content,andGSHPxactivityoftheperitonealtissuehomogenateweredetectedinaccordancewiththeinstructionofthekit.1.5 Pathologicalexaminationofperitonealtissues

Parietalperitonealtissuesweredippedin10%neutralformalinfor24h,andthendehydratedingradedethanolseries,andembeddedinparaffin.Then4μmthickparaffinsectionsweremadeand

63

Page 4: Epithelial to ... · intheperitonealfibrosismodelgroup,αSMAex ...

EMTofperitonealmesothelialcellsmediatedbyoxidativestressinperitonealfibrosisrats DUANShaobin,etal.

underwentconventionaldeparaffinizationandhydration,andHE andMassonstainweredone.Thesliceswereplacedunderopticalmicroscopetoexaminethepathologicalchanges.Tenfieldspersliceand5sitesperfieldwereobserved.ThethicknessoftheperitonealtissueswasaccuratelymeasuredbyPIPS2020pathologicalimageanalysissystem.1.6 Immunohistochemicalstaining

Paraffinsectins(4μm)deparaffinizedwithdimethylbenzeneanddehydratedseriallyin100% to75% ethanol.Thenheatmediatedantigenretrievalwasdoneusingcitratebuffer.ThesectionswereaddedwithrabbitantiratprimaryantibodyofαSMA(1∶250)andEcadherin(1∶200),respectively.Thesectionswereplacedin4℃ overnightandthenin37℃ thermostaticovenfor30min.Thentheyreactedwiththesecondaryantibodythatmarkedbybiotin,andunderwentDAB colorationandhaematoxylincounterstain.PBSbufferprocessedsliceswereusedasnegativecontrol.ThesectionswereplacedinopticalmicroscopetoobservetheproteinexpressionofαSMAandEcadherin.1.7 Westernblot

Threeomentum samplesfrom eachgroupweretakenoutoftheliquidnitrogencontainers,and100gramofthemwereweighedout,ground,andmixedwithcooledcelllysissolutiontomakehomogenate.Thehomogenatewerecentrifugedat4℃ and1000r/minfor20min.Thesupernatantwascollected,putintotubes,andkeptat-70℃.ThentheproteinconcentrationwasdetectedwithBCA.Twentymicrogramoftotalproteinwasprepared,andtransferredtoPVDF film aftersodium dodecylsulfatepolyacrylamidegelelectropheresis(SDSPAGE).Itwasblockedwith5% skimmedmilkatroomtemperaturefor1h,thenaddedwithblockingbufferdilutedprimaryantibodyofαSMA (1∶1000),Ecadherin(1∶1000)andβactin(1∶1500),swungforonenightat4℃,andwashedwithTBSTfor4times,5mineachtime.Thenitwasaddedwithhorseradishperoxidase(HRP)markedsecondaryantibody.Onehourlater,itwaswashedwith

TBSTfor4times,5minforeachtime.Thenitwasincubatedwithelectrochemiluminescence(ECL)reactionliquidfor5min.ImaginganalysiswasdonewithKodak4000MM chemiluminescenceimager,andtheexpressionofβactinonthesamefilmwasdetectedascontrolgroup.1.8 Statisticalanalysis

Datawerepresentedasmean±standarddeviation(x±s).ThestatisticalanalyseswereobtainedbythestatisticalsoftwareSPSS16.0andOnewayANOVA.Normalitytestandhomogeneityofvariancetestweredoneatfirst,andthosewhichdidnotmeetthenormaldistributionorhomogeneityofvarianceweretestedwithDunnett’sT3 test.Forthosewhichmetthenormaldistributionandhomogeneityofvariance,thecomparisonsbetweentwoofthemeansofthemultisampletestsweretestedwiththeLeastSignificantDifference(LSD).P<0.05wasconsideredashavingstatisticalsignificance.

2 RESULTS

2.1 WeightchangesofratsineachgroupTheratswereweighedonthemorningofthe

1st,8th,15th,22nd,and30thdaywhentheirstomachswereempty.Onthe22ndday,1ratintheperitonealfibrosismodelgroupdied.Thepairedcomparisonoftheweightofratsindifferentgroupsweredone,nostatisticaldifferencewasfound(P>0.05,Tab.1).2.2 Comparisonofperitonealfunctionandoxidativestressrelatedindexesofratsindifferentgroups

ThevolumeofultrafiltrationandD4/D0 ofratsintheperitonealfibrosismodelgroupwereobviouslylowerthanthoseofratsinthenormalcontrolgrouporthesalinegroup(P<0.05),andtheperitoneumthickness,MTG,D/Pcr,MDA,andGSHPxactivitywereobviouslyhigherthanthoseofratsinthenormalcontrolgrouporthesalinecontrolgroup(P<0.01);thevolumeofultrafiltration,D4/D0,andGSHPxactivityofratsintheprobucolinterven

73

Page 5: Epithelial to ... · intheperitonealfibrosismodelgroup,αSMAex ...

中南大学学报(医学版),2011,36(1)  http://xbyx.xysm.net

tiongroupwereobviouslyhigherthanthoseofratsintheperitonealfibrosismodelgroup(P<0.05,P<0.05,P<0.01,respectively),andtheperitoneumthickness,MTG,D/Pcr,andMDAwereobviously

lower(P<0.01,P<0.01,P<0.05,P<0.01,respectively);allindexesofratsinnormalgroupwerenotstatisticallydifferentfromthoseofratsinthesalinegroup(P>0.05,Tab.2).

Tab.1 Changeofbodyweightineachgroupratseveryweek(x±s,g)

Time/d Normalcontrolgroup(n=6) Salinecontrolgroup(n=6) Modelgroup(n=5) Interventiongroup(n=6)

1 200.33±9.95 199.50±10.84 203.40±12.84 200.50±9.44

8 243.00±18.13 244.50±14.24 251.40±15.47 242.50±15.98

15 271.50±18.54 285.83±23.41 288.80±28.15 278.50±23.40

22 298.67±17.12 306.17±26.66 317.60±33.43 318.83±27.95

30 307.50±14.92 318.67±30.64 327.20±30.15 325.17±27.15

Tab.2 Comparisonofperitonealfunctionandperitonealoxidativestressindexesineachgrouprats(x±s)

IndexesNormalcontrolgroup

(n=6)

Salinecontrolgroup

(n=6)

Modelgroup

(n=5)

Interventiongroup

(n=6)

Thicknessofperitoneum/μm 6.39±1.15 8.40±1.49 25.02±4.28 9.73±1.98##

Volumeofultrafiltration/mL 10.01±4.10 8.09±4.11 -2.56±5.16 5.03±3.36#

D/Pcr 0.57±0.10 0.59±0.11 0.75±0.13 0.61±0.08#

D4/D0 0.42±0.05 0.35±0.08 0.16±0.07 0.32±0.08#

MTG/(mmol/kg) 3.71±0.38 3.97±0.29 6.55±0.49 4.59±0.32##

MDA/(nmol/mgprot) 3.01±1.04 4.19±1.03 8.62±0.96 5.42±1.10##

GSHPx/(U/mgprot) 309.08±26.68 249.25±55.05 174.57±31.10 260.15±39.13##

  Comparedwiththenormalcontrolorthesalinecontrolgroup,P<0.05,P<0.01;comparedwiththeperitonealfibrosismodelgroup,#P<

0.05,##P<0.01.

2.3 HistomorphologyofperitoneumInthenormalcontrolgroupandthesalinecon

trolgroup,peritoneumofratwascoveredbyaflatlayerofperitonealmesothelialcells.Intheperitonealfibrosismodelgroup,themesothelialcellswereballorpillar shaped. Shedding of mesothelialcells,baredfiber,obviousthickeningofmatrix,infiltrationoffibroblasts,monocytesandmacrophages,depositionoffibrinoidstuff,andobviousincreaseofnewlygeneratedsmallvesselsintheperitonealtissueswerefoundinthisgroup.Besides,theparietalperitoneumwasobviouslythickerthanthatofratsinthe controlgroup. In the probucolinterventiongroup,themesothelialcellswereplatandpartiallyshed,baredfiberwaslittle,thickeningofmatrixwasnotobvious,interstitialinflammatorycellsevidentlyreduced,newlygeneratedsmallvesselsinthe

peritonealtissuesevidentlyreduced,andtheparietalperitoneumwasobviouslythinnerthanthatofratsintheperitonealfibrosismodelgroup(Fig.1).2.4 ProteinexpressionofαSMAandEcadherin

Theresultsofimmunohistochemistryshowedthatinthenormalcontrolgroupandthenormalsalinegroup,Ecadherinexpressionwascontinuous,andαSMAwasnotexpressed;intheperitonealfibrosismodelgroup,Ecadherinproteinwasnotexpressed,andαSMAexpressionwasobviouslyupregulated;intheprobucolinterventiongroup,Ecadherinproteinwaspartiallydiscontinuouslyexpressed,andαSMAproteinwaspartiallyexpressed(Fig.2).TheresultofWesternblotindicatedthattheexpressionofαSMAproteinintheperitonealtissueswasupregulatedcomparedwiththatofthecontrolgroup,while

83

Page 6: Epithelial to ... · intheperitonealfibrosismodelgroup,αSMAex ...

EMTofperitonealmesothelialcellsmediatedbyoxidativestressinperitonealfibrosisrats DUANShaobin,etal.

theexpressionofEcadherinproteinwassignificantlydownregulated(P<0.01);theexpressionofαSMAproteinintheperitonealtissuesofratsintheprobucolinterventiongroupwassignificantlydown

regulatedcomparedwiththatofratsintheperitonealfibrosismodelgroup(P<0.01),whiletheexpressionofEcadherinproteinwassignificantlyupregulated(P<0.01,Fig.3).

HEstaining              Massonstaining

Fig.1 Massonstainingshowingthehistomorphologyofperitonealtissueineachgrouprats(×100).A,B:Normalcontrol

group;C,D:Salinecontrolgroup;E,F:Peritonealfibrosismodelgroup;G,H:Probucoltreatmentgroup.

93

Page 7: Epithelial to ... · intheperitonealfibrosismodelgroup,αSMAex ...

中南大学学报(医学版),2011,36(1)  http://xbyx.xysm.net

αSMA            Ecadherin

Fig.2 ImmunohistochemicalstainingshowingproteinexpressionofαSMAandEcadherininperitonealtissueofeachgroup

rats(SP,×100).A:ProteinexpressionofαSMAinthenormalcontrolgroup;B:ProteinexpressionofEcadherininthe

normalcontrolgroup;C:ProteinexpressionofαSMAinthesalinecontrolgroup;D:ProteinexpressionofEcadherininthe

salinecontrolgroup;E:ProteinexpressionofαSMAintheperitonealfibrosismodelgroup;F:ProteinexpressionofEcad

herinintheperitonealfibrosismodelgroup;G:ProteinexpressionofαSMAintheprobucoltreatmentgroup;H:Proteinex

pressionofEcadherinintheprobucoltreatmentgroup.

04

Page 8: Epithelial to ... · intheperitonealfibrosismodelgroup,αSMAex ...

EMTofperitonealmesothelialcellsmediatedbyoxidativestressinperitonealfibrosisrats DUANShaobin,etal.

!""""""""""""""#""""""""""""""""""""$"""""""""""""""""%

%#"&'

%$"&'

()*+,

-)./012

34/.567812

94./012

!#:;&'

%$"&'

<8=>?@

!;;;;;;;;;;;;;;;;;;;;;#;;;;;;;;;;;;;;;;;;;;;$;;;;;;;;;;;;;;;;;;;;;%

A

B

%

#

:

C7D701E7;F

)*+,;D7E7D@

C7D701E7;

3/.567812;D7E7D@

!G!

!

:GH

:GA

:GI

:GB

:GJ

:G%

:G$

:G#

:G!

:

<8=>?@

!;;;;;;;;;;;;;;;;;;;;;#;;;;;;;;;;;;;;;;;;;;;;$;;;;;;;;;;;;;;;;;;;;;;;%

KL

MM

NN

MM

!O""""""""""""""""""#""""""""""""""""""$"""""""""""""""""%

,

P

Fig.3 WesternblotshowingtheexpressionsofαSMAandEcadherininperitonealtissueofeachgrouprats.A:Electro

phoretogramofWesternblot;B:Histogramoftheresults.1:Normalcontrolgroup;2:Salinecontrolgroup;3:Peritonealfi

brosismodelgroup;4:Probucoltreatmentgroup.Comparedwiththenormalcontrolgrouporsalinecontrolgroup,P<

0.01;comparedwiththeperitonealfibrosismodelgroup,##P<0.01.

3 DISCUSSION

DuringlongtermPD,therecurringofperitonitisandincompatibilityofPDFwillcausestructuralandfunctionalchangesofperitoneum,andfinallyresultinperitonealfibrosis,sclerosis,andultrafiltrationfailure.Researches[12]showedthatultrafiltrationfailurecausedbyperitonealfibrosisisthemainreasonforpatientstowithdrawPD;peritonealfibrosismayrelatetolongterm exposuretohighglucose,hyperosmolality, lactate, glucose degradationproducts, and advanced glycation end products.However,themechanismsofperitonealfibrosisarestillnotclear[2,11].

DOUetal.[10]establishedtheratperitonealfibrosismodelbyintraperitonealinjectionof4.25%glucosePDFinthedoseof100mL/kgfor28d.Inthisresearch,itwasfurtherconfirmedthatusing4.25% glucosePDFcansuccessfullycloneratperitonealfibrosismodel,causingthedecreaseofultrafiltrationvolumeandD4/D0,increaseofD/PcrandMTG,andthickeningofparietalperitoneum.Noevidentdifferencewasfoundbetweentheultrafiltrationvolume,D4/D0,D/Pcr,MTG,thicknessofparie

talperitoneum,andpathologicalconditionofratsinthenormalgroupandthoseofratsinthesalinegroup,indicatingthatintraperitonealinjectionofsalinedidnotcauseperitonealfibrosisonrats,whichwasin accordance with whathad been repor

ted[1011].

Studies[1011] haveshowedthatincreasedoxidativestressexistsinPDpatients,andROSaregeneratedthroughvariousways.ROScausedamagestoperitonealmesothelialcellsandsomeothercells.Highglucose, highosmolality, low pH, glucosedegradationproducts,andadvancedglycationendproductsmayinduceincreasedoxidativestressinperitoneumandproducelargeamountofROS,whichleadtotheupregulatedexpressionoffibronectin,unbalanceofcoagulationfibrolysissystem,depositionofextracellularmatrix,releaseofinflammatorymediator,activationoftranscriptionfactors,overexpressionoffibrogeniccytokinessuchastransforminggrowthfactor(TGF)β1,connectivetissuegrowthfactor(CTGF)andsoon,andfinallyresultinperitonealfibrosis[5,7,1213].Itwasfoundinthepresentstudythat,therewasnostatisticaldifferencebetweentheoxidativestressindexesMDAandGSHPxofratsinthesalinegroupandthoseofratsinthe

14

Page 9: Epithelial to ... · intheperitonealfibrosismodelgroup,αSMAex ...

中南大学学报(医学版),2011,36(1)  http://xbyx.xysm.net

normalgroup;4.25% PDFcouldinducetheincreaseofMDAlevelandthedecreaseofGSHPxactivity;obviousfeaturesofperitonealfibrosisappearedintheperitonealtissuesoftheperitonealfibrosismodelrats;theMDA levelofratsintheprobucolinterventiongroupdecreased,whiletheactivityofGSHPxincreasedcomparedwiththoseofratsintheperitonealfibrosismodelgroup;thenewsmallvesselsintheperitonealtissuesdecreasedobviouslyintheprobucolinterventiongroup.

EMTisthekeyofperitonealfibrosisintheearlystage,andisreversible[34].Thetransdifferentiatedmyofibroblastsmaybethemaincellsthatareinvolvedintheperitonealfibrosis.EcadherinexpressiononthesurfaceofperitonealmesothelialcellsandtheαSMAexpressiononthesurfaceofmyofibroblastsmayreflectindirectlythestateofEMT.Oxidativestressplaysapartroleinthetransdifferentiationofrenaltubularepithelialcellsandthetransdifferentiationofstellatecellstomyofibroblastsintheprocessofhepaticfibrosis.Thecontinuousoxidativedamageofperitoneum willcauseperitonealfibrosis[14].Butthereisstillnodirectproofthatoxidativestressplaysaroleinthetransdifferentiationoftheperitonealmesothelialcells.SomeresearcherstriedtoinhibittheoxidativestressofperitonealfibrosismodelsbyusingantioxidantvitaminC,angiotensinconvertingenzymeinhibitor,angiotensinreceptorblocker,HMGCoAreductaseinhibitors(statins),Chineseherbalmedicine,proteaseinhibitoraminoguanidine,glutathioneprecursorandsoon[1517],whichhascertaineffectinpreventingperitonealfibrosis,butstillcannotstopit.Probucolisoneofthebestantioxidantsatpresentwhichservestoantiinflammatory,antioxidation,andantifibrosisandprotectthekidney.Butitisstillnotreportedwhetheritismediatedbyantioxidantthatprobucolreversesthetransdifferentiationofperitonealmesothelialcellstoprotecttheperitoneum.Itwasfoundinthisresearchthattherewasnostatisticaldifferencebetweenthetransdifferentiationindexes,theexpressionofαSMA andEcadherinofratsinthesaline

groupandthoseofratsinthenormalcontrolgroup;intheperitonealfibrosismodelgroup,αSMAexpressionintheperitonealtissueswasupregulatedandEcadherinexpressiondisappeared;aftertheapplication ofprobucolto inhibitthe oxidativestress,theactivityofGSHPxintheperitonealtissuesincreasedsignificantly,theMDAlevelloweredsignificantly,theexpressionofαSMAproteinwasdownregulated,andtheexpressionofEcadherinproteinwasupregulated.Alltheseresultsindicatedthatintraperitonealinjectionofsalinedidnotcausetransdifferentiation ofperitonealmesothelialcells;bothoxidativestressandperitonealmesothelialcelltransdifferentiationexistedinperitonealfibrosismodelrats;iftheoxidativestresswasinhibited,theperitonealmesothelialcelltransdifferentiationwouldbepartiallyinhibited,whichindicatingthatoxidativestressplayedapartroleintheperitonealmesothelialcelltransdifferentiationofrats.

Inconclusion,using4.25% PDFcansuccessfullybuildperitonealfibrosismodelofrats;oxidativestressplayedapartroleintheperitonealmesothelialcelltransdifferentiation;intraperitonealinjectionofsalinedidnotcausetransdifferentiationofperitonealmesothelialcells;theapplicationofantioxidantprobucolcanpartiallyreversethetransdifferentiationofperitonealmesothelialcells,improvethetransportfunctionofperitoneum,andprotecttheperitoneuminperitonealfibrosismodelratstoacertainextent.

REFERENCES:

[1] WeinhandlED,FoleyRN,GilbertsonDT,etal.Pro

pensitymatchedmortalitycomparisonofincidenthemodialysis

andperitonealdialysispatients[J].JAm SocNephrol,

2010,21(3):499506.

[2]  Kim Y L.Updateonmechanismsofultrafiltrationfailure

[J].PeritDialInt,2009,29(S2):S123S127.

[3] LoureiroJ,SchilteM,AguileraA,etal.BMP7blocks

mesenchymalconversionofmesothelialcellsandpreventsperi

tonealdamageinducedbydialysisfluidexposure[J].Neph

rolDialTransplant,2010,25(4):10981108.

[4] AroeiraLS,AguileraA,SelgasR,etal.Mesenchymal

conversionofmesothelialcellsasamechanism responsible

forhighsolutetransportrateinperitonealdialysis:roleof

24

Page 10: Epithelial to ... · intheperitonealfibrosismodelgroup,αSMAex ...

EMTofperitonealmesothelialcellsmediatedbyoxidativestressinperitonealfibrosisrats DUANShaobin,etal.

vascularendothelialgrowthfactor[J].AmJKidneyDis,

2005,46(5):938948.

[5] NascimentoMM,SulimanME,SilvaM,etal.Effectof

oralNacetylcysteinetreatmentonplasmainflammatoryand

oxidativestressmarkersinperitonealdialysispatients:apla

cebocontrolledstudy[J].PeritDialInt,2010,30(3):

336342.

[6] ShimizuM,IshibashiY,TakiF,etal.Endothelin(B)

receptorblockerinhibitshighglucoseinducedsynthesisoffi

bronectininhumanperitonealmesothelialcells[J].PeritDi

alInt,2006,26(3):393401.

[7] KuoHT,LeeJJ,HsiaoHH,etal.Nacetylcysteinepre

ventsmitochondriafrom oxidativeinjuryinducedbyconven

tionalperitonealdialysatein human peritonealmesothelial

cells[J].AmJNephrol,2009,30(3):179185.

[8] KoyaD,HayashiK,KitadaM,etal.Effectsofantioxida

ntsindiabetesinducedoxidativestressintheglomeruliof

diabeticrats[J].JAmSocNephrol,2003,14(8Suppl

3):S250S253.

[9] DuJ,WangL,LiuX,etal.Januskinase2/signaltrans

ducersandactivatorsoftranscriptionsignalinhibitionregulates

protectiveeffectsofprobucolonmesangialcellstreatedwith

highglucose[J].BiolPharmBull,2010,33(5):768

72.

[10] 窦献蕊,余学清,王文健,等.一种新的大鼠慢性腹

膜纤维化动物模型的建立[J].中华肾脏病杂志,

2004,20(6):446449.

DOUXianrui,YUXueqing,WANGWenjian,etal.Anew

chronicanimalmodelofperitoneal[J].ChineseJournalof

Nephrology,2004,20(6):446449.

[11] FusshoellerA.Histomorphologicalandfunctionalchangesof

theperitonealmembraneduringlongterm peritonealdialysis

[J].PediatrNephrol,2008,23(1):1925.

[12]NohH,HaH,YuM R,etal.AngiotensinⅡ mediates

highglucoseinducedTGFbeta1andfibronectinupregulation

inHPMCthroughreactiveoxygenspecies[J].PeritDial

Int,2005,25(1):3847.

[13]KyudenY,ItoT,MasakiT.TGFbetalinducedbyhigh

glucoseiscontrolledbyangiotensinconvertingenzymeinhibi

torandangiotensinIIreceptorblockeronculturedhuman

peritonealmesothelialcells[J].PeritDialInt,2005,25

(5):483491.

[14]GotloibL,WajsbrotV,ShostakA.Ashortreviewofexper

imentalperitonealsclerosis:from micetomen[J].IntJ

ArtifOrgans,2005,28(2):97104.

[15]HeydrickSJ,ReedKL,CohenPA,etal.Intraperitone

alasministrationofmethyleneblueattenuatesoxidativestress,

increasesperitonealfibrinolysis,andinhibitsintraabdominal

adhesionformation[J].JSurgRes,2007,143(2):

311319.

[16]DumanS,SenS,DumanC,etal.Effectofvalsartanver

suslisinoprilonperitonealsclerosisinrats[J].IntJArtif

Orqans,2005,28(2):156163.

[17] KucukH F,KaptanogluL,KurtN,etal.Theroleof

simvaststinonpostoperativeperitonealadhesionformationin

ananimalmodel[J].EurSurgRes,2007,39(2):

98102.

(EditedbyGUOZheng)

34