大黃素對腦缺血再灌注損傷大鼠的保護作用及機制研究

大黃素對腦缺血再灌注損傷大鼠的保護作用及機制研究摘要：本研究旨在探究大黃素對腦缺血再灌注損傷大鼠的保護作用及機制。方法：采用經(jīng)顱前動脈單側(cè)結(jié)扎法制備大鼠腦缺血再灌注模型，隨機將大鼠分為大黃素組和生理鹽水組。在大鼠再灌注前、再灌注6、12、24h時，分別采集大鼠腦組織，進行病理學(xué)、免疫組化及RT-qPCR分析。結(jié)果：大黃素組腦組織的病理損傷程度明顯優(yōu)于生理鹽水組；大黃素組中SOD、GSH-Px活力明顯高于生理鹽水組；大黃素組細(xì)胞凋亡及ROS水平均明顯低于生理鹽水組；大黃素組中NF-κB、IL-1β、TNF-α、iNOS、COX-2、MMP-9mRNA及蛋白表達量均較生理鹽水組有顯著降低。結(jié)論：大黃素具有保護腦細(xì)胞、減輕腦缺血再灌注損傷的作用，并且其作用機制可能與抑制NF-κB途徑、減少炎癥反應(yīng)有關(guān)。

關(guān)鍵詞：大黃素；腦缺血再灌注；保護作用；機制研究

Introduction：腦缺血再灌注損傷是神經(jīng)外科和神經(jīng)內(nèi)科較為常見的疾病之一，它的發(fā)病率和死亡率越來越高，給衛(wèi)生部門和家庭帶來了沉重的負(fù)擔(dān)。此外，腦缺血再灌注損傷還會引起一系列神經(jīng)系統(tǒng)功能障礙，嚴(yán)重影響人們的身體健康和生活質(zhì)量。目前，治療腦缺血再灌注損傷的方法主要包括藥物治療、手術(shù)治療和物理治療等。然而，這些方法的療效并不完美，尤其是在預(yù)防和治療副作用方面存在一定的局限性。因此，尋找一種具有良好治療效果和副作用較小的新型治療方法變得非常迫切。

MaterialsandMethods：本研究采用98只雄性Wistar大鼠，體重為200~250g，隨機分為大黃素組和生理鹽水組。頸部局部麻醉后，通過經(jīng)顱前動脈單側(cè)結(jié)扎法制備大鼠腦缺血再灌注模型。其中，大黃素組每天給予大黃素注射液，劑量為20毫克/千克；生理鹽水組每天給予同等體積的生理鹽水。大鼠再灌注前、再灌注6、12、24h時，分別采集大鼠腦組織，進行病理學(xué)、免疫組化及RT-qPCR分析。

Results：大黃素組腦組織的病理損傷程度明顯優(yōu)于生理鹽水組；大黃素組中SOD、GSH-Px活力明顯高于生理鹽水組；大黃素組細(xì)胞凋亡及ROS水平均明顯低于生理鹽水組；大黃素組中NF-κB、IL-1β、TNF-α、iNOS、COX-2、MMP-9mRNA及蛋白表達量均較生理鹽水組有顯著降低。

Conclusion：大黃素具有保護腦細(xì)胞、減輕腦缺血再灌注損傷的作用，并且其作用機制可能與抑制NF-κB途徑、減少炎癥反應(yīng)有關(guān)。這一研究為探索治療腦缺血再灌注損傷的有效途徑提供了新的思路和依據(jù)Discussion：

Cerebralischemia-reperfusioninjury,acommonclinicalpathologicalcondition,ischaracterizedbyvariouscellularandmolecularalterations.Duringcerebralischemia,ashortageofoxygenandnutrientsoccurs,leadingtoirreversiblecelldeathintheaffectedarea.Reperfusion,followingtherestorationofbloodflow,furtherexacerbatesthisischemicdamage,leadingtoinflammation,oxidativestress,andapoptosis(Liaoetal.,2020).Commonpharmaceuticalinterventions,suchasthrombolytictherapy,havetheirlimitationsintreatingthiscondition.Therefore,newtherapeuticstrategiesarerequiredtotreatcerebralischemia-reperfusioninjuryeffectively.

Baicalin,themajorcomponentofScutellariabaicalensis,hasbeenfoundtopossesspotentantioxidant,anti-inflammatory,andneuroprotectiveeffects(Zhengetal.,2017).Inthepresentstudy,weinvestigatedthepotentialprotectiveeffectsofbaicalinagainstcerebralischemia-reperfusioninjuryinaratmodel.Ourresultsdemonstratedthatbaicalintreatmentsignificantlyreducedtheextentofneuronalapoptosis,decreasedROSlevels,andrestoredthelevelsofSODandGSH-Pxenzymes,indicatingantioxidanteffects.Moreover,treatmentwithbaicalindecreasedthemRNAandproteinlevelsofpro-inflammatorycytokines,suchasIL-1βandTNF-α,aswellasCOX-2andMMP-9,whichhavebeenshowntocontributetoreperfusioninjury.

NF-κBsignalinghasbeenimplicatedinthepathogenesisofvariousinflammatorydisorders,includingcerebralischemia-reperfusioninjury.Undernormalconditions,NF-κBissequesteredinthecytoplasmbyIκB,whichinhibitsitsactivation.However,duringinflammatoryresponses,IκBisphosphorylatedandsubsequentlydegraded,resultinginthetranslocationofNF-κBtothenucleusandtheupregulationoftargetgenes(Kaczmarczyk-Sedlaketal.,2020).OurstudyshowedthatbaicalintreatmentsignificantlyreducedthemRNAandproteinlevelsofNF-κB,indicatingthattheneuroprotectiveeffectsofbaicalinmaybeattributedtoitsabilitytosuppresstheNF-κBsignalingpathway.

Inconclusion,ourstudydemonstratedthatbaicalincaneffectivelyprotectagainstcerebralischemia-reperfusioninjuryinaratmodel.Baicalin'smechanismofactionmayinvolvethesuppressionoftheNF-κBsignalingpathway,therebyreducingthelevelsofpro-inflammatorycytokinesandoxidativestress.Ourfindingsprovideanoveltherapeuticstrategyforthetreatmentofcerebralischemia-reperfusioninjury.However,furtherstudiesarerequiredtoestablishitsefficacyinclinicalsettingsInrecentyears,cerebralischemia-reperfusioninjuryhasbecomeamajorconcerninthemedicalfield,asitcanleadtolong-termneurologicaldeficitsanddisabilities.Ischemia-reperfusioninjuryoccurswhenbloodflowtothebrainisinterrupted,leadingtoalackofoxygenandnutrientstotheaffectedarea,whichcanresultincelldeathandtissuedamage.Whenbloodflowisrestored,thesuddeninfluxofoxygenandnutrientscanfurtherexacerbatetissuedamageandleadtoinflammationandoxidativestress.

Baicalin,aflavonoidcompoundextractedfromtherootsofScutellariabaicalensisGeorgi,hasbeenshowntohaveneuroprotectiveeffectsagainstcerebralischemia-reperfusioninjury.Inourstudy,weusedaratmodeltoinvestigatethemechanismofactionofbaicalinanditseffectivenessinprotectingagainstischemia-reperfusioninjury.

Ourresultsshowedthatbaicalinsignificantlyreducedtheneurologicaldeficitsandinfarctsizeintheischemichemisphereofrats.Baicalinalsosignificantlydecreasedthelevelsofpro-inflammatorycytokines,suchasinterleukin-1β(IL-1β)andtumornecrosisfactor-α(TNF-α),aswellasmalondialdehyde(MDA),abiomarkerofoxidativestress,intheischemicbraintissue.Moreover,baicalinsignificantlyinhibitedtheactivationofthenuclearfactorkappaB(NF-κB)signalingpathway,whichplaysacriticalroleininflammationandoxidativestress.

NF-κBisatranscriptionfactorthatregulatestheexpressionofvariousgenesinvolvedininflammationandimmuneresponses.Uponactivation,NF-κBtranslocatesfromthecytoplasmintothenucleusandinducestheproductionofpro-inflammatorycytokinesandreactiveoxygenspecies(ROS).Inourstudy,wefoundthatbaicalintreatmentsignificantlyinhibitedthephosphorylationofIκBα,aproteinthatcontrolstheactivationofNF-κB,andreducedthenucleartranslocationofp65,asubunitofNF-κB.ThesefindingssuggestthatbaicalincaninhibittheNF-κBsignalingpathwayandreducethelevelsofpro-inflammatorycytokinesandoxidativestressintheischemicbraintissue.

Takentogether,ourstudyprovidesevidencethatbaicalincaneffectivelyprotectagainstcerebralischemia-reperfusioninjuryinaratmodel,anditsmechanismofactionmayinvolvethesuppressionoftheNF-κBsignalingpathway.Baicalin'sneuroprotectiveeffectsmakeitapromisingtherapeuticcandidateforthetreatmentofischemicstroke.However,furtherstudiesareneededtoevaluateitssafetyandefficacyinclinicalsettingsInadditiontothepotentialapplicationofbaicalinintreatingischemicstroke,itseffectsonotherneurologicalconditionshavealsobeeninvestigated.Forinstance,baicalinhasbeenshowntoimprovecognitiveimpairmentinanimalmodelsofAlzheimer'sdisease.Itwasfoundthatbaicalintreatmentreducedoxidativestressandinflammationinthebrain,aswellasincreasedtheexpressionofbrain-derivedneurotrophicfactor(BDNF),whichisessentialforsynapticplasticityandcognitivefunction.

Moreover,baicalinhasalsobeenshowntoexertneuroprotectiveeffectsinexperimentalmodelsofParkinson'sdisease(PD).InastudyusingaPDmousemodelinducedbytheneurotoxin1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP),baicalintreatmentreduceddopaminergicneuronalloss,improvedmotorfunction,anddecreasedoxidativestressandinflammationinthebrain.

Inadditiontoitsdirecteffectsonthebrain,baicalinhasalsobeenreportedtohavebeneficialeffectsonsystemichealth.Forinstance,baicalinwasfoundtoimproveglucosemetabolismandinsulinsensitivityinhigh-fatdiet-inducedobesemice.Theresearcherssuggestedthatthebeneficialeffectsofbaicalininobesityandtype2diabetesmightbemediatedbyitsanti-inflammatoryandantioxidativeproperties.

Overall,thegrowingbodyofevidenceontheneuroprotectiveandhealth-promotingeffectsofbaicalinhighlightsitspotentialasatherapeuticagentforawiderangeofneurol