探讨蛇毒心脏毒素（ＣＴＸ）对人肺癌Ａ５４９细胞株的遗传毒性。方法应用眼镜蛇毒（ＣＴＸ）处理体外培养的人肺癌Ａ５４９细胞株，通过细胞生长速率、有丝分裂指数（ＭＩ）、细胞周期动力学指数（ＣＫＩ）、银染核仁组织区计数（ＡｇＮＯＲ）、姐妹染色单体交换（ＳＣＥ）频率、二倍体细胞比率的分析，观察ＣＴＸ所产生的遗传毒性作用。结果ＣＴＸ能明显抑制肺癌Ａ５４９细胞的ＤＮＡ复制过程和ｒＲＮＡ的合成，且随着浓度增大，癌细胞受抑制程度越大。用２ｍｇ／ＬＣＴＸ作用肺癌细胞后，ＳＣＥ频率比对照组明显下降（Ｐ＜０．０１），但对照组和实验组出现的二倍体细胞比率差异不明显（Ｐ＞０．０５）。结论眼镜蛇毒ＣＴＸ可抑制肺癌细胞的生长恶性程度，但使其恶性表型逆转的作用不明显。 To investigate the genotoxicity of venom cardiotoxin (CTX) on human lung cancer cell line A549. Methods Human lung adenocarcinoma A549 cells were cultured in vitro with CTX. Cell growth rate, mitotic index (MI), cell cycle kinetic index (CKI), AgNOR, Monomer exchange (SCE) frequency, diploid cell ratio analysis to observe the genotoxic effects of CTX. Results CTX could significantly inhibit the DNA replication process and the synthesis of rRNA in lung cancer A549 cells. With the increase of concentration, CTX could inhibit the proliferation of cancer cells. Compared with the control group, the frequency of SCE was significantly decreased (P <0.01). However, there was no significant difference in the ratio of diploid cells between the control group and the experimental group (P> 0.05). Conclusion Cobra venom CTX can inhibit the growth of lung cancer malignancy, but to reverse the role of malignant phenotype is not obvious.