目的：研究维生素Ｋ３（Ｍｅｎ）降低ＥＡＣ／Ｄｏｘ细胞对阿霉素（Ｄｏｘ）的抗药性．方法：测定谷胱甘肽（ＧＳＨ），细胞膜流动性及谷胱甘肽Ｓ转移酶（ＧＳＴ）活性．细胞存活力以甲基四唑蓝法测定．结果：ＥＡＣ／Ｄｏｘ细胞ＧＳＨ，ＧＳＴ及膜流动性均较ＥＡＣ细胞增加（Ｐ＜００１）．Ｄｏｘ对ＥＡＣ／Ｄｏｘ细胞ＩＣ５０为２２３（１５８－２８８）ｍｇ·Ｌ－１．Ｍｅｎ５或１０ｍｇ·Ｌ－１可降低ＥＡＣ／Ｄｏｘ细胞ＧＳＨ（Ｐ＜００１），１ｍｇ·Ｌ－１对ＧＳＨ无影响（Ｐ＞００５），但可降低细胞膜流动性（Ｐ＜００５）．Ｍｅｎ１，５或１０ｍｇ·Ｌ－１可使ＤｏｘＩＣ５０降低到９．６（７８－１１３），６０（２８－９２），或５３（３９－６７）ｍｇ·Ｌ－１（Ｐ＜００１）．结论：Ｍｅｎ在体外降低ＥＡＣ／Ｄｏｘ细胞对Ｄｏｘ抗药性与对ＧＳＨ的耗竭有关． PURPOSE: To study the effect of vitamin K3 (Men) on the resistance of doxorubicin (Dox) to EAC / Dox cells. Methods: Glutathione (GSH), cell membrane fluidity and glutathione S-transferase (GST) activity were measured. Cell viability was determined by methyltetrazolium blue assay. Results: The GSH, GST and membrane fluidity of EAC / Dox cells were higher than those of EAC cells (P <001). The IC50 of Dox to EAC / Dox cells was 223 (158-288) mg · L -1. Men5 or 10 mg · L-1 could reduce the GSH of EAC / Dox cells (P <001), 1 mg · L-1 had no effect on GSH (P> 005), but could reduce the membrane fluidity 05). Men 1, 5 or 10 mg · L-1 reduced DoxIC50 to 9.6 (78-113), 60 (28-92), or 53 (39-6  7) mg · L-1 (P <001). Conclusion: Men can decrease the drug resistance of Dox and the depletion of GSH in EAC / Dox cells in vitro.