The damage of H-22 tumor cells induced by ultrasound activated protoporphyrin Ⅸ was investigated (1.43 MHz, 1 W/cm2). And the bio-mechanism of sonodynamic therapy (SDT) was also discussed. Trypan blue exclusion method was used to analyze the viability of H-22 cells. Scanning electronic microscope (SEM) and transmission electron microscope (TEM) were used to observe the ultrastructure of cell surface and interior. The production of reactive oxygen species (ROS) was assayed by fluorescence labeling technique, and the thiobarbituric acid (TBA) method was used to measure the lipid peroxidation levels. The results indicated that the membrane system of tumor cell was damaged and PPⅨ-sonodynamic therapy could induce the tumor cell to produce ROS which damaged the membrane of cell and induced lipid peroxidation. These results imply that PPⅨ-sonodynamic therapy has the significant damage effects on H-22 tumor cells and the lipid peroxidation could be increased by ROS. Based on these results mentioned above, PPⅨ-sonodynamic therapy can kill tumor cells through its direct and indirect effects on the membrane system of cells.

ultrasound; protoporphyrin Ⅸ; H-22 tumor cell; sonodynamic therapy