Biological effects of shock waves: cell disruption, viability, and proliferation of L1210 cells exposed to shock waves in vitro.

L1210 cells were exposed in suspension to shock waves generated with a Dornier XL1 lithotripter. After 1000 discharges at 25 kV, the number of nondisrupted cells was 15% and the number of trypan blue excluding cells was 7% as compared to 100% in sham treated controls; the shock-wave effect was more prominent at higher voltages and less prominent at higher discharge numbers when compared at similar electrical input energies. Overall proliferation of cells which were trypan blue negative after exposure exceeded 70% of the proliferation of sham treated controls, except after 1000 shocks at 25 kV, where proliferation was reduced to 42%. The latter reduction in proliferation was found to be due to a reduced growth for 24 h after exposure, with a return to normal proliferation during the following days. Limiting dilution analysis revealed that the reduced growth was mainly due to a transitory increase of the doubling time and not to a reduction of the number of proliferating cells. Cell disruption by shock waves was completely inhibited by exposing the cells at an elevated pressure of 101 atmospheres, pointing to the possible involvement of cavitation in the shock wave effect.