Ultrastructure of sarcoma 180 cells after ultrasound irradiation in the presence of sparfloxacin.

Background: Sonodynamic synergistic antitumor effects have been well described to date, but detailed ultrastructural studies in this field are still lacking.

Materials And Methods: A suspension of sarcoma 180 cells was exposed to ultrasound (US) in the presence of sparfloxacin (SPFX), one of the new quinolone antibiotics, at 2 W (0.64 W/cm2) for 30 seconds. The antitumor effect was evaluated by the survival rate of cells and cell morphology by scanning and transmission electron microscopy.

Results: After US irradiation, the survival rate of tumor cells in the SPFX-added group was 30.9%, significantly lower than 78.7% in the control group (p = 0.0002). Most cells in the control group were spherical, but in the SPFX-added group the cells were aspherical. Cell membranes were often ruptured and numerous pores of various sizes were observed. Some cells were totally disintegrated.

Conclusion: The most characteristic changes of the synergistic antitumor activities of US and SPFX were on the cell membrane.