目的 探讨黄芪甲苷对耐药人乳腺癌细胞MDA-MB-231/DOX多药耐药的逆转作用。方法 以噻唑蓝（MTT）法测定黄芪甲苷的细胞毒性及其处理前后乳腺癌细胞对阿霉素的敏感性或耐药性变化。采用乙醇注入法-硫酸铵梯度法构建共载阿霉素-黄芪甲苷的脂质体（LPs-DOX/AS），并评价其对乳腺癌细胞多药耐药的逆转作用，采用流式细胞术测定LPs-DOX/AS对细胞凋亡的影响。结果 黄芪甲苷在实验浓度范围内对乳腺癌细胞无明显细胞毒性；与黄芪甲苷联用后，阿霉素对MDA-MB-231、MDA-MB-231/DOX细胞的半数抑制浓度（IC₅₀）值均下降（P<0.05），并且对耐药细胞的干预效果更明显（P<0.01）。脂质体包载后的LPs-DOX/AS-IV比游离DOX/AS-IV对2种乳腺癌细胞的IC₅₀值均下降（P<0.05），同样对耐药株的效果更明显（P<0.01）。经LPs-DOX/AS-IV处理的耐药株细胞凋亡率也显著高于游离药物组（P<0.05）。结论 黄芪甲苷对人乳腺癌细胞MDA-MB-231对阿霉素多药耐药具有很好的逆转作用，黄芪甲苷与阿霉素联用及其脂质体共递送体系的开发可以有效逆转或增敏乳腺癌的多药耐药。

Objective To investigate the reversal effect of astragaloside IV on multidrug resistance of MDA-MB-231/DOX in breast cancer cells. Methods The cytotoxicity of astragaloside IV and sensitivity or drug resistance of breast cancer cells to doxorubicin (DOX) before and after treatment were determined by MTT assay. Liposome co-delivery system containing doxorubicin and astragaloside IV (LPs-DOX/AS) was constructed by ethanol injection-ammonium sulfate gradient method. The reversal effect of LPs-DOX/AS on multidrug resistance of breast cancer cells was determined by MTT method. The effect of LPs-DOX/AS on apoptosis was determined by flow cytometry. Results Astragaloside IV had no significant cytotoxicity to breast cancer cells in the experimental concentration range. After combined with astragaloside IV, the IC₅₀ values of DOX on MDA-MB-231 and MDA-MB-231/DOX cells decreased (P < 0.05), and the intervention effect on drug-resistant cells was more significant (P < 0.01). Compared with free DOX/AS-IV, the IC₅₀ values of LPs-DOX/AS-IV on both breast cancer cells decreased (P < 0.05), and the effect on drug-resistant strains was more significant (P < 0.01). The apoptosis rate of drug-resistant strains treated with LPs-DOX/AS-IV was also significantly higher than that of free drug group (P < 0.05). Conclusion Astragaloside IV has reversal effect on multidrug resistance of human breast cancer cell MDA-MB-231 to doxorubicin. The combination of astragaloside IV and doxorubicin and its liposome co-delivery system can effectively reverse or sensitize multidrug resistance in breast cancer.

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