Objective      To investigate the antitumor effect of ultrasound-mediated chemotherapy

i.e. combination of microbubble agent and cisplatin exposing to low-intensity/low-frequency ultrasound

on human cervical cancer Hela cells.       Methods      Hela cells were divided into 5 groups: control group (C)

cisplatin group (P)

cisplatin combined ultrasound group (PU)

microbubble enhanced ultrasound (UM)

and cisplatin combined microbubble ultrasound group (PUM). Nonfocused ultrasound with 1MHz fr

equency and 400 kPa acoustic pressure was applied to treat the cells in log-phrase of growth. Cell apoptosis was measured by Hoechst33342 staining. Cell proliferation rate was examined by CCK-8 assay. The proportion of cell apoptosis was determined by flow cytometry after cell were treated for 24 h and double-stained with Annexin V-FITC/PI.       Results      The IC

50

of cisplatin was 4.882 μg/mL in Hela cells. Flow cytometry analysis showed that apoptosis of PUM group was significantly higher than other groups (P0.05). The apoptotic rate of PUM group was 58.1%

which was 40% higher than that in PU group. Cell growth was markedly inhibited in PUM group compared with other group detected by CCK-8 assay. Also

the apoptotic cells had typical morphological changes observed with inverted fluorescence microscope after Hoechst33342 staining.       Conclusion      Low-intensity and low-frequency ultrasound combined with microbubble agent can enhance the cytotoxicity of cisplatin to Hela cells by inhibiting proliferation and promoting apoptosis.