AstudyonthemechanismofactionofactivevitaminD3throughregulatingtheNF-?资Bsignalingpathwayinrenalprotectionofdiabeticnephropathyrats

Abstract:

Objective：①ToinvestigatethemechanismofactionofactivevitaminD3throughregulatingtheNF-κBsignalingpathwayinrenalprotectionofratswithtype2diabeticnephropathy.②TodeterminetheoptimalconcentrationofvitaminDinthetreatmentofdiabeticnephropathy.Methods：SeventySprague-Dawleyratswererandomlydividedintonormalcontrolgroup（10rats）andDNmodelgroup（60rats），andtheDNmodelgroupwasfurhterdividedintopeanutoilgroup，irbesartangroup，low-dosevitaminDgroup，medium-dosevitaminDgroup，andhigh-dosevitaminDgroup，with10ratsineachgroup.Thenormalcontrolgroupwasfedwithroutinediet，whiletheratsinthemodelgroupweread－ministeredabove-mentioneddrugsbygavage.Theratswerethensacrificedandweighedafter6weeks.Andfastingbloodglucose（FBG）wasmeasuredafterbloodsampling，and24-hoururinewasalsocollectedtocalculateurinevolumeandquantify24-hoururineprotein.RenaltissuewasretainedandHEstainingwasusedtoobservethepathologicalchangesofrenaltissue.Meanwhile，real-timefluorescentquantitativePCRwasusedtodeterminetheexpressionofnuclearfactor-kappaB（NF-κB）mRNAanditsdownstreammonocytechemotacticprotein-1（MCP-1）mRNAinrenaltissue，andtheproteinexpressionofinflammatoryfactors，NF-κBandMCP-1，wasmeasuredbyWesternblot.Results：①ThelevelsofFBGand24-hoururineproteininthelow-dosevitaminDgroupweresignificantlylowerthanthoseinthepeanutoilgroup[18.20（16.25，21.25），32.24（26.09，37.68）vs.23.55（22.75，24.60），72.52（50.38，84.93），P<0.05].②Inthenormalcontrolgroup，HEstainingshowedthattheglomerularmorphologywasintact，themesangialareahadnoobvioushyperplasia，andthecapillarylumenandloopswerebothregularlyshaped；inthepeanutoilgroup，theglomerularvolumewasreduced，themesangialareasignificantlybroadened，theglomerularmesangialcellsproliferated，andcapillarywallbecamethickenedaswell.Theirbesartangroupshowedlesshyperplasiacomparedwiththepeanutoilgroup.Thehigh-，medium-，andlow-dosevitaminDgroupsallhadabroad－enedglomerularmesangialarea，butthelow-dosegroupexhibitedthelowestdegreeofbroadening.③ThemRNAlevelsofNF-κBandMCP-1inthelow-dosevitaminDgroupweresignificantlylowerthanthoseinthenormalcontrolgroupandthepeanutoilgroup（1.72±0.002，0.67±0.01vs.3.57±0.40，3.57±0.37，allP<0.05）.However，therewasnosignificantdifferencebetweentheirbesartangroupandthelow-dosevitaminDgroup.④TherewerenosignificantdifferencesbetweenthesegroupsregardingtheexpressionofNF-κBprotein.Thelow-dosevitaminDgrouphadasignificantreductionintheexpressionofMCP-1proteincomparedwiththepeanutoilgroupandthemedium-dosevitaminDgroup（0.47±0.17vs.0.90±0.30，1.22±0.18，0.93±0.43，allP<0.05）.Conclusion：①VitaminDcaneffectivelyalleviaterenalinjuryindiabeticnephropathybydown-regulationoftheNF-κBinflammatorysignalingpathway.②Asindicatedinthestudy，0.03μg/（kg·d）inthelow-dosevitaminDgroupistheoptimalconcentrationforre－nalprotectionindiabeticnephropathy.