[Effect of ultrasound activating hematoporphyrin on the activities of antioxidative enzymes in mouse hepatoma 22].

This investigation was made with regard to the influences of ultrasound combined with hematoporphyrin on the activities of antioxidative enzyme in ascites hepatoma 22 (H-22) tumor cells, and to a better understanding of the potential biological mechanism of sonodynamic therapy which involved the damage to cells. Combined with 100 microg/ml hematoporphyrin, high intensity focused ultrasound sonication at a frequency of 1.43 MHz and an intensity level of 2.0 W/cm2 was delivered to H-22 tumor cells for 1 min. The viability of cells was evaluated by typan-blue blue exclusion test. The intracellular reactive oxygen species (ROS) levels were determined by 2',7'-dichlorofluorescein diacetata (DCFH-DA). Enzymatic chemical methods were used to measure the activities of key antioxidative enzymes. The results indicated that the cell damage rate of ultrasound combined with hematoporphyrin was significantly higher than that of the treatment with ultrasound alone, and hematoporphyrin alone had no killing effect on H-22 cells. The level of ROS in cell suspension was significantly increased, and the key antioxidative enzyme activities were obviously decreased after treatment with the combined use of ultrasound and hematoporphyrin. We speculated that the decreased activities of key antioxidative enzymes in cells might be involved in mediating the killing effect on H22 cells in sonodynamic therapy.