In vitro cytotoxic activity of lithotripter shock waves combined with adriamycin or with cisplatin on L1210 mouse leukemia cells.

The effect of a combined treatment with shock waves generated by a lithotripter and Adriamycin or cisplatin was examined in cells that acutely survived exposure to shock waves and proliferated afterwards. Batches of 2 x 10(6) cells were exposed to the respective drug for 50 min or for 50 min plus 72 h. During the 50-min drug exposure 500 shock waves were applied at 25 kV. The growth as a percentage of the control was determined after 72 h by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cells treated with shock waves alone showed a growth inhibition as compared to control cells. For a 50-min drug exposure with Adriamycin the dose enhancement ratio did not exceed 1.3. For a 50-min drug exposure with cisplatin at concentrations of 0.5 micrograms/ml and 5.0 micrograms/ml, growth (as a percentage of the control) after combined treatment was significantly reduced as compared to cisplatin treatment alone; the dose enhancement ratio was 3.2 at 50% growth compared to the control. This indicates that shock waves can increase the susceptibility of L1210 cells to cisplatin. For a 50-min plus 72-h drug exposure no effect of an additional treatment with shock waves, as compared to chemotherapy alone, could be observed.