The effect of ultrasound with a frequency of 1.34 MHz and intensity of 1W/cm2 in presence of hematoporphyrin on EAT tumor cells was studied. The changes in the ultrastructure of the samples obtained at different time points were observed by the scanning electron microscope.HO apoptosis detecting kit was used to identify the morphologic changes of EAT cells after the ultrasound treatment at different time points.The expression of apoptosis associated protein Caspase-8 were detected by immunohistochemistry techniques.The data shown that the apoptosis in EAT tumor cells can be induced by ultrasonically activated hematoporphyrin,and the apoptosis was enhanced gradually by the ultrasounic treatment.The activity of Caspase-8 were apparently up-regulated during apoptosis.The results above indicate that sonochemically activated hematoporphyrin mediates the apoptosis of tumor cells,and the mechanism may be related to the expression of Caspase-8 cleaving function depended on membrane receptor activate on pathways.

ultrasound; hematoporphyrin; Ehrlich ascites tumor（EAT）; cell apoptosis