Bleomycin, which is the most widely used drugs in electrochemotherapy, requires oxygen to be able to make single- or double-strand brakes in DNA. However, the concentration of oxygen in tumours can be lower than 1%. The aim of this study was to find out whether oxygen concentration in the medium in which cells loaded with bleomycin are incubated, affects the effectiveness of electrochemotherapy in vitro. Experiments were carried out on mouse hepatoma MH-22A cells. Cells were loaded with bleomycin by using a single square-wave electric pulse (2 kV/cm, 100 μs) under normoxic conditions, seeded into Petri dishes, and grown under normoxic and hypoxic conditions. Cell viability was determined by means of a colony-forming assay. We demonstrated that when cells loaded with bleomycin were incubated in hypoxia (0.2% O₂), up to 5.3-fold higher concentrations of bleomycin were needed to kill them in comparison with cells grown in normoxia (18.7% O₂).

博来霉素是电化学疗法中使用最广泛的药物，它需要氧气才能在DNA中产生单链或双链制动器。但是，肿瘤中的氧气浓度可能低于1％。这项研究的目的是发现载有博来霉素的细胞在培养液中的氧气浓度是否会影响体外电化学疗法的有效性。在小鼠肝癌MH-22A细胞上进行了实验。通过在常氧条件下使用单个方波电脉冲（2 kV / cm，100μs）向细胞加载博来霉素，接种到陪替氏培养皿中，并在常氧和低氧条件下生长。细胞存活力通过集落形成测定法确定。我们证明了将载有博来霉素的细胞在缺氧条件下孵育（0.2％O₂），与正常氧下生长的细胞（18.7％O ₂）相比，杀死博来霉素的浓度最高需要高5.3倍。