两种价态铬(ⅲ、ⅳ)遗传损伤分析与机制分析

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1、硕士学位沦文两种价态铬(III．VI)遗传损伤研宄及机制分析ACOⅣ口AⅪSONOFT】Rj．ANDHEXAVALENTCHROMIUM0NGENETICDAMAGEABSTRACTIntheprocessofindustrialization，heavymetalsarewidelyusedandreleasedintotheenvironment．Thesemetalsaredifficulttobedegradedbiochemically，andthusthreatenthehealthofhumanbeingsthroughthefoodc

2、hain．Therefore，increasingattentionhasbeenpaidworldwidetoheavymetalpollutionproblems．Internationally，CrisconsideredtObeoneofthefourmajorpollutantstogetherwithHg，Cd，andPb，whichexistsmostlyintWOvalencestatesinnature：hexavalentchromium[chromium(V1)]andtrivalentchromium[chromium(111

3、)]．Cr(VI)speciesareconsideredasthemosttoxicformofchromium，andconfirmedasahumancarcinogenbytheInternationalAgencyforResearchonCancer(IARC)in1987．Cr(111)isacknowledgedmuchlesstoxic，andhavethetherapeuticeffectondiabetes．However，Cr(IIt)asessentialtraceelementsremainscontroversial．T

4、hespecialbiochemicalrole&chromiumhasyettobeidentified．Inthisstudy，byusingyeastSUP4—0mutagenesisassaysystem，themutationrateoftheyeaststrainSJR576一PinducedbyCr(111)andCr(VI)Wasdetected．Theresultindicatedthatl50pMCrCl3and300pMCr03inducedsimilarmutationfrequencies．Itisabout2．5x10。a

5、ndalmostfivetimesofspontaneousmutationfrequency．ItsuggeststhatthedegreeofgeneticdamagetotheyeastcellsofCr(III)isnotlessthanCr(VI)，Furthermore，intracellularDNAdamageWasdetectedinyeastcellsandanimalcells(Jurkat)treatedwithdifferentvalencestatesofchromiumsaltsbySingleCellGetElectr

6、ophoresis．TheresultshowedthatDNAdamadgeofCr(III)isstrongerthanthatofCr(V1)inbothceils．．rPreviousstudieshavedemonstratedthatglutathioneisanimportantintracellularreductiveagentofCr(VI)．Hereweinvestigatedtheeffectofthreekindschromiumsalts(potassiumdichromate，chromium仃ioxide，chromi

7、umchloride)onintracellularGSHcontent。Theresultsshowedthatpotassiumdichromateandchromiumtrioxide，whilenotchromiumchloride，reduced③硕士学位论文两种价态铬(III，Ⅵ)遗传损伤研究及机制分析theintracellularGSHcontent．ItindicatedthattherearedifferentintracellularbiochemicalactionsbetweenCr(III)andCr(Vi)andthei

8、rdetoxificationmechanismsarealsodif俺rent．／nvitro，three