Epithelial to ... · intheperitonealfibrosismodelgroup,αSMAex ...
Transcript of 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
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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.
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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
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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
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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
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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.
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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.
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EMTofperitonealmesothelialcellsmediatedbyoxidativestressinperitonealfibrosisrats DUANShaobin,etal.
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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
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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.
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