| Sudan I(1-phenylazo-2-hydroxynaphthol),a synthetic lipid soluble azo pigment,is widely used in various industrial fields.It is forbidden to be used as food additiveagent because of its potential danger to human body.However,food containing Sudan was found on themarket of China and some other countries in Europe and America,and has draw next extensive attention.In 1975 the International Agency for Research on Cancer(IARC),assessed SudanI as a Group 3 carcinogen.With respect to Sudan I genotoxicity data,positive results were observed both in vivo and in vitro upon metabolic activation.The liver is the target site of Sudan I toxicity.Sudan I is metabolized by several routes,reactive oxygen sPecies (ROS) are produced.The aim of this study was to asses the genotoxic effects of SudanI in vitro and to elucidate the mechanism of oxidative DNA damage. In this research,we selected liver cells of WISTAR mice,which is the target site cells of Sudan I toxicity and retains many of the functions of normal liver cells.So liver cells have been shown to be a suitable system for genotoxicity testing. Research has indiated that,Sudan I may make damage to the DNA of many organs,and it is a wide damage factor in human body.The metabolisms of Sudan I in animals and our human bodies are very complicated,the detection of biological toxicity is very difficult, and the biological toxicity varies from one to another.In this study,liver cells of WISTAR mice for study,single-cell gel electrophoresis experiments,DPC experiments and MDA experiments were applied to explore Sudan I genotoxicity,and its molecular mechanism of potential toxicity.The results are as follows:1.Sudan I caused DNA breakageAcademics have not been able to reach a consensus whether Sudan I can lead to DNA breakage.Single cell gel electrophoresis(SCGE) was used in the present study to detect the DNA damage induced by Sudan I in liver ceils of mice.The results showed that Sudan I could induce DNA damage in mice,and the damage effect increased with the concentrations of Sudan I,indicating the dose-dependent manner of Sudan I toxicity. All the concentration of Sudan I containing 25μmol/L,50μmol/L and 100μmol/L could induce extremely significant DNA breakage in the cells of liver(p<0.01).2.DNA-protein erosslinks induced by Sudan IThere are a certain amount of DNA-protein crosslinks(DPC) in normal cells,which are normal connection between DNA and nuclein.Therefore,DPC is important to support the cell growth.Excessive DPC can be induced by environmental pollutants and carcinogen.Compared with other types of DNA damage,DPC is hard to be repaired,and DPC can only exist in the single strand DNA,which shows,that DPC can be induced during replication and transcription.So DPC has serious influence to DNA configuration and functions and can cause loss of some important genes(such as tumor suppressor gene).Excessive DPC is a pathological phenomenon and a serious genetic damage in DNA.In this study,SDS-KC1 precipitation was used to detect DPC formation in liver cells after Sudan I exposure.This result confirmed the Sudan I can induce DPC in liver cells, and the trend is increasing at concentration from 25μmol/Lto 100μmol/L3.Sudan I induce oxidative damageWhen Sudan I was at concentration of 25μmol/L,the content of MDA in the liver cells are low which compared to the blank group.But this one reveals obviously the low-dose-dependent manner.When Sudan I was at concentration of 50μmol/L,the content of MDA in the liver cells are higher than blank group but have no significant difference.Meanwhile,when Sudan I was at concentration of 100μmol/L,the highest concentration,the content of MDA in the liver cells are higher and have extremely significant(p<0.01).The experimentation can testify that Sudan I can conduce the serious oxidative damage in the cells of liver.
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