In vitro exposure to 0.57-MHz electric currents exerts cytostatic effects in HepG2 human hepatocarcinoma cells.

Capacitive-resistive electric transfer (CRET) therapy is a non-invasive technique currently applied to the treatment of skin, muscle and tendon injuries that uses 0.45-0.6 MHz electric currents to transdermically and focally increase the internal temperature of targeted tissues. Because CRET electrothermal treatment has been reported to be more effective than other thermal therapies, it has been proposed that the electric stimulus could induce responses in exposed tissues that are cooperative or synergic with the thermal effects of the treatment. Previous studies by our group, investigating the nature of the alleged electric response, have shown that short, repeated stimuli with 0.57-MHz currents at subthermal levels could provoke partial, cytotoxic effects on human neuroblastoma cells in vitro. The aim of the present study was to investigate the response from another human cell type, the human hepatocarcinoma HepG2 line, during and after the exposure to 0.57-MHz CRET currents at subthermal densities. The electric stimuli provoked a decrease in the proliferation rate of the cultures, possibly due to an electrically-induced blocking of the cell cycle in a fraction of the cellular population.