Conflicting Data on Biological Systems Treated with Electrical Direct Current

Abstract

Recently direct electrical current (DC) has been extensively used and investigated for its possible exploitation in control of cell proliferation in vitro and in vivo, including both murine tumor models and some human malignancies. Several mechanisms have been proposed for the DC antitumor effect. In vitro cell proliferation has been reported to be controlled by direct currents with intensities ranging from 360 nA (1) up to 1.5 mA (2). In these reports, both enhancement and suppression of cell proliferation in malignant and normal cells were reported. Becker reports in his communication (3) that with low currents (i.e., 360 nA), stimulation was achieved at positive and negative electrodes (1) and here enhanced cell proliferation in a cathodic chamber, but slowed cell division by the cessation of mitosis in anodic chamber (3). The use of higher currents (0.2-1.5 mA) resulted in inhibition of cell proliferation in normal and malignant cells (2, 4). This proportional relationship that suggests itself is not easy to accept and has already been rejected by Lyte et al. (5), who found a narrow window (17 µA) in current level for the inhibition, whereas adjacent levels of current resulted in stimulation of malignant cells in vitro.