Cell-type-specific response to shock waves of suspended or pelleted cells as analysed by flow cytometry or electrical cell volume determination.

Shock-wave-induced cell damage of suspended or pelleted bladder cancer cells was analysed with the flow cytometric propidium iodide (PI)/fluorescein diacetate assay, and electrical volume determination using the CASY 1 analyser system and growth curves. The CASY system revealed a smaller fraction of suspended RT4 cells with impaired membrane integrity than the flow cytometric assay. No differences were found for pelleted RT4 cells and suspended J82 cells. The discrepancies of the two viability assays indicated a different response of the cell membrane to shock waves which was dependent on the exposure system and the cell type. Growth curves indicated delayed cell death for suspended RT4 cells and exclusively immediate cell death for pelleted RT4 cells and suspended J82 cells. PI positive suspended RT4 cells were morphologically intact while pelleted RT4 cells and suspended J82 cells were mainly disrupted. From these data it can be concluded that intracellular or membrane alterations seem to be correlated with the occurrence of cavitational effects while cell disruption can likewise occur by the direct impact of the shock wave.