氯化锌和N-乙酰半胱氨酸对镉诱导人肝癌细胞株SMMC-7721凋亡的影响研究

The effects of zinc chloride and N-acetyl cysteine on apoptosis of SMMC-7721 cell line induced by cadmium

目的研究氯化锌(ZnCl2)和N-乙酰半胱氨酸(N-acetyl cysteine,NAC)对氯化镉(CdCl2)致人肝癌细胞SMMC-7721增殖及凋亡的影响。方法体外培养的人肝癌细胞SMMC-7721分别以0、20、40、80、160和320μmol/L的CdCl2处理3、6、12、24、48h,ZnCl2预处理和NAC预处理组在CdCl2处理前分别以100μmol/L的ZnCl2和5mmol/L的NAC预处理24h,应用MTT法检测细胞相对存活率,流式细胞仪Annexin V-PI双标法检测细胞凋亡百分率。结果随着镉处理浓度的增高和时间的延长,SMMC-7721细胞存活率逐渐降低;SMMC-7721细胞凋亡率随着CdCl2浓度的增加而逐渐增加,40μmol/L及以上镉处理组与对照组相比,凋亡率显著增加,P<0.01;与相同剂量的单纯Cd处理组相比,Zn预处理组细胞凋亡率差异无统计学意义,P>0.05,与40、80μmol/L镉处理组相比,相同剂量的NAC预处理组细胞凋亡百分率显著下降,P<0.05,其余镉处理剂量的NAC预处理组细胞凋亡百分率差异无统计学意义,P>0.05。结论一定剂量的ZnCl2预处理不能显著降低镉诱导的SMMC-7721细胞凋亡,而NAC预处理可在一定程度上显著降低镉诱导的肝癌细胞凋亡百分率。

Objective To study the effect of Zinc chloride and N-acetyl cysteine （NAC） on proliferation and apoptosis of human hepatocellular carcinoma cell SMMC 7721 induced by cadmium chloride. Methods SMMC-7721 cell were incubated with 0,20,40,80,160,and 320μmol/L CdCl2 for 3 h,6 h,12 h 24 h and 48 h. The cells in groups of zinc and NAC pretreatment were treated with 100μmol/L of ZnCl2and 5mmol/L NAC for 24 h before incubated with CdCl2. The relative viability was observed by MTT. The rate of apoptosis was measured by Flowcytometry Staining of cells with phosphatidylserine （PS）-annexin-V. Results Cells viability were time and dose dependent decreased with the dose increase of cadmium. Compared with 0μmol/L cadmium, the apoptosis rate increased obviously in the incubating cell with 40,80.150. 320μmol/L cadmium（P 〈0.01）. Zinc pretreatment did not show the inhibition effects on the apoptosis rate of SMMC-7721 （P〉0.05）. Compared with CdCl2 group, the apoptosis rate of NAC pretreatment group were significantly decreased only when the CdCl2 dose were 40 and 80μmol/L（P〈0.05）. Conclusion Zinc chloride could not reduce the apoptosis rate of SMMC-7721 while NAC might reduce the apoptosis rate of SMMC-7721 induced by cadmium chloride at certain concentration.