邻苯二甲酸单(2-乙基)己酯对MCF-7细胞DNA的氧化损伤

目的:研究邻苯二甲酸单(2-乙基)己酯(mono-2-ethylexyl phthalate,MEHP)对人乳腺癌MCF-7细胞DNA氧化损伤的作用。方法:分别用不同浓度的MEHP(6.25、12.5、25、50和100μmol/L)和二甲基亚砜(溶剂对照,0.1%)处理MCF-7细胞12和24 h后用MTT比色法检测细胞的存活率。再分别于染毒后1.5、3、6、12和24 h,测定丙二醛(malondialdehyde,MDA)、超氧化物歧化酶(superoxide dismutase,SOD)、谷胱甘肽过氧化物酶(glutathione peroxidase,GSH-Px)和细胞8-羟基脱氧鸟苷(8-hydroxy-2′-deoxyguanosine,8-OHdG)水平。结果:与对照组比较,MEHP染毒12 h,6.25和12.5μmol/L组细胞的存活率显著增加(P0.05)。MEHP染毒24 h,在较高浓度处理组(≥25μmol/L)的细胞存活率显著降低(P0.05);各处理组细胞的SOD活性有所增加,细胞MDA水平、GSH-Px活性以及8-OHdG生成量无显著变化(P0.05)。当MEHP染毒MCF-7细胞较短时间(1.5、3和6 h)时,各处理组MDA水平和8-OHdG生成量均显著升高(P0.05),而SOD和GSH-Px活性则显著性降低(P0.05)。结论:一定浓度MEHP作用在短时间内(1.5、3和6 h)可引起MCF-7细胞的氧化应激反应,并触发细胞DNA的氧化性损伤,具体调控机制有待深入研究。

Effects of mono-2-ethylexyl phthalate on oxidative DNA damage in MCF-7 cells

OBJECTIVE：Oxidative DNA-damaging effects of mono-2-ethylexyl phthalate（MEHP） on MCF-7 cells were investigated.METHODS：MCF-7 cells were treated with MEHP at various concentrations （6.25,12.5,25,50 and 100μmol/L） or dimethyl sulphoxide alone（DMSO,solvent control,final concentration 1‰）. Cell proliferation was measured by the MTT assay at 12 and 24 h after the treatment.At the time points（1.5,3,6,12 and 24 h）,the content of malondialdehyde（MDA） and activities of superoxide dismutase（SOD） and glutathione peroxidase （GSH-Px） were measured using the corresponding kits.The level of（8-hydroxy-2＇-deoxyguanosine,8-OHdG） in MEHP-treated cells was estimated using high-pressure liquid chromatography with electrochemical detection HPLC-ECD method. RESULTS：At 12 h after treatment,cell proliferation rates significantly increased in MEHP-treated groups（6.25 and 12.5μmol/L,P0.05 for both）.However,cell proliferation rates significantly decreased at 24 h after treatment,in the higher MEHP-treated groups（25-100μmol/L,P0.05 for all）.There were no significant changes in the levels of MDA,GSH-Px and 8-OHdG（P0.05 for all）.After MCF-7 cells were treated with MEHP for short periods（1.5,3 and 6 h）,the levels of MDA and 8-OHdG in all treatment groups were increased（P0.05）,but SOD and GSH-Px activities were reduced（P0.05 for all）.CONCLUSION：Short periods（≤6 h） of treatment with MEHP at a certain concentration induced oxidative stress in MCF-7 cells,and accelerated DNA oxidative damage.The underlying mechanisms of MEHP mediated oxidative DNA damage MCF-7 cells need to be investigated.