Griffin D T, Dodd N J, Zhao S, Pullan B R, Moore J V
Paterson Institute for Cancer Research, Christie Hospital (NHS) Trust, Manchester, UK.
Br J Cancer. 1995 Jul;72(1):31-4. doi: 10.1038/bjc.1995.272.
Low-level direct electrical current has shown promise as a potential therapeutic modality (direct current therapy; DCT) in the treatment of malignant disease, including metastases, but to date much experimental work has been empirical and has added little to our knowledge of the mechanisms involved. As a prerequisite to a clinical trial for metastases in the liver, we have employed an in vivo liver model to examine the quantitative and qualitative relationships between electrode polarity, charge and tissue necrosis. Two distinct regions of necrosis were induced, distinguishable histologically and by magnetic resonance imaging: (i) a cylindrical region of primary necrosis centred on the electrode, its volume directly proportional to the charge passed, but greater at the anode than cathode; and (ii) a wedge-shaped infarct, apex at the electrode and base extending to the liver edge. The extent of this infarct was again greater at the anode than the cathode, but showed a sigmoidal relationship with charge. Results indicate pH changes at the electrodes as likely mediators of tissue injury, but show also that significant distant ischaemic injury can occur as a consequence of primary damage. These findings should be considered when selecting tumours for possible direct current therapy and when determining the sites of electrode placement.
低强度直流电已显示出作为一种潜在治疗方式（直流电疗法；DCT）用于治疗包括转移瘤在内的恶性疾病的前景，但迄今为止，许多实验工作都是经验性的，对我们所涉及机制的了解贡献甚微。作为肝脏转移瘤临床试验的先决条件，我们采用了一种体内肝脏模型来研究电极极性、电荷与组织坏死之间的定量和定性关系。诱导出了两个不同的坏死区域，在组织学上和通过磁共振成像都可区分：（i）以电极为中心的原发性坏死的圆柱形区域，其体积与通过的电荷量成正比，但在阳极处比阴极处更大；（ii）一个楔形梗死灶，顶点在电极处，底部延伸至肝脏边缘。该梗死灶的范围在阳极处同样比阴极处更大，但与电荷呈S形关系。结果表明电极处的pH变化可能是组织损伤的介质，但也表明原发性损伤可能导致显著的远处缺血性损伤。在选择可能进行直流电疗法的肿瘤以及确定电极放置部位时，应考虑这些发现。
