叶酸对Cr(Ⅵ)所致的HaCaT细胞DNA损伤的作用研究

Effect of folic acid on DNA damage induced by Cr(Ⅵ) in HaCaT cells

目的:探讨六价铬[Cr(Ⅵ)]对人角质形成细胞(HaCaT)的DNA损伤情况及叶酸的干预作用。方法:MTT法检测Cr(Ⅵ)及叶酸对细胞增殖活力的影响,选取接近IC50的Cr(Ⅵ)10.00μmol/L浓度作为染毒组,染毒前以不同浓度叶酸(80、160、320 nmol/L)作为干预组,正常条件培养的细胞作为对照组。单细胞凝胶电泳法(SCGE)检测细胞DNA尾长(μm)、尾部DNA含量(%)和尾矩。结果:Cr(Ⅵ)作用HaCaT细胞24 h的IC_(50)值为15.88μmol/L;DNA损伤比较,染毒组较对照组增加(P<0.05),160、320 nmol/L叶酸干预组较染毒组低(P<0.05),320 nmol/L叶酸干预组DNA损伤与对照组比较差异无统计学意义(P>0.05)。结论:Cr(Ⅵ)对HaCaT细胞有毒作用并可造成细胞DNA损伤,叶酸可减轻并扭转Cr(Ⅵ)所致的细胞DNA损伤。

Objective： To investigate the DNA damage of hexavalent chromium [ Cr （ Ⅵ ） ] on human keratinocytes （HaCaT） and the effect of folic acid on DNA damage induced by Cr（ Ⅵ ）. Methods：MTT assay was used to detect the effect of Cr（ Ⅵ） and folic acid on the cell viability. The concentration of Cr（ Ⅵ ） which was near by IC50 was selected as the later experimental group. Pretreatment cells were treated with different concentrations （80,160 and 320 nmol/L） of folic acid as the intervention group and normal conditioned cells were used as the control group. DNA tail length （μm） ,tail DNA content （%） and tail moment were measured by single cell gel electrophoresis （SCGE）. Results ：The ICso of hexavalent chromium [ Cr（ Ⅵ） ] in HaCaT ceils at 24 h was 15.88 μ mol/L. The DNA damage in the experimental group was higher than that of the control group （P〈0.05）. DNA damage in the intervention group with the folic acid at 160 or 320 nmol/L was lower than the experimental group （P〈0.05）.The DNA damage in the intervention group with the folic acid at 320 nmol/L was significantly lower than the experimental group （P〈0.05）, and was no significant difference with the control group. Conclusion：Cr（ Ⅵ ） can be toxic to HaCaT cells and cause DNA damage. Folic acid can reduce and reverse the DNA damage induced by Cr（Ⅵ）.