Objective: To investigate the safety dose of Vitamin D and the protective effect ofVitamin D against DNA damage in mice induced by Benzene and CP.Methods:(1) CHL cells was cultured in medium containing1,25(OH)2D3(0,10,20,50and100nM), mixture S9and CP(50μg/ml). Chromosomal aberrations werevisually detected under a microscope in metaphase CHL cells. γ-H2AX foci formationwas measured by immunofluorescence. Level of reactive oxygen species (ROS) in CHLcells was measured using flow cytometry.(2) Male ICR mice were randomly dividedinto three groups. Mice were injected with Vitamin D3at dose of0,500and1000IU fortwo weeks. Mice wereinjected intraperitoneally with40mg/kg cyclophosphamideafter the last administration of Vitamin D. Micronucleated in mice bone marrowerythrocytes was detected using flow cytometry. The DNA damage in mouse peripheralblood lymphocytes was measured by comet assay.(3) ICR mice were randomly dividedinto three groups, i.e. negative control group, benzene treatment and benzene-Vitamin Dtretment group. Vitamin D treating group forcedly injected with Vitamin D from theweek before the day received the benzene, healthy controlling group and benzenetreating group were administered with tea oil only. Benzene-Vitamin D treatment groupwere adminstrated with benzene with the models of subcutaneous injection after secondinjection of Vitamin D. Micronucleated in mice bone marrow erythrocytes was detectedusing flow cytometry. The DNA damage of mouse peripheral blood lymphocytes wasmeasured by comet assay. Level of ROS in bone marrow cells was measured using flowcytometry.Results:(1) Number of chromosomal aberration in CHL cells increasedsignificantly after treated with cyclophosphamide in vitro. The significantly increasednumber of γ-H2AX focus indicating a serious damage in CHL cells caused bycyclophosphamide.1,25(OH)2D3at10,50and100nM reduced chromosomalaberration and γ-H2AX.(2) fMNPCE, comet assay indicators and number of γ-H2AX focus increased significantly in vivo. Compared with positive group, fMNPCEdecreased significantly. The significantly decreased number of comet assay indictorsand γ-H2AX focus indicating that vitamin D can reduce double-stranded breaks (DSBs)micronucleus rate and the number of γ-H2AX focus were significantly increased afterradiation.(3) Compared with normal control group, fMNPCE and comet assayindicators showed that DNA damage of benzene treating group is severe, ROS levels ofbone marrow cells were significantly increased. Micronucleus rate and comet assayindex decreased significantly after VD processing, ROS levels of Vitamin D treatinggroup were significantly lower than those of benzene group.Conclusion:(1) Active vitamin D reduced chromosome aberration rate, which wasrelated to active vitamin D reduced γ-H2AX expression.(2) Vitamin D reduced themicronucleus formation to play a protective effect of genome, mainly because it canease the DNA damage caused by cyclophosphamide,specifically via a dose-dependentdecrease in DSBs.(3) Our result suggests that Vitamin D can alleviate DNA damageinduced by benzene, might be associated with ameliorating antioxidant. |