Objective To investigate the antitumor effect and its mechanism of microbubble contrast combined with Mitoxantrone exposed to low-frequency ultrasound on human breast cancer cell MCF-7. Methods MTT method was applied to examine the growth inhibition of MCF-7 treated with Mitoxantrone. MCF-7 cells were randomly divided into 4 groups:Mitoxantrone group (group D), ultrasound+Mitoxantrone group (group U+D), ultrasound+microbuble +Mitoxantrone group (group U+M+D) and control group (group C). The cytoactive of each group was examined with MTT. The intracellular drug content in each group was measured with high performance liquid chromatography. The morphology of MCF-7 cells apoptosis was observed with transmission electron microscopy (TEM). Results The IC_(50) of Mitoxantrone was 2.87 μg/ml. The differences of cytoactive among all groups were significant (P<0.05). The intracellular drug content of group U+M+D was higher than that of group U+D, and the latter was higher than that of group D. The morphological changes of apoptosis were observed with TEM. Conclusion Low-frequency ultrasound can promote intracellular drug content as to enhance the sensitivity of chemotherapy drugs on tumor cells, and this effect can be enhanced by microbubble contrast exposure to low-frequency ultrasound.

Objective To prepare HCC-targeted lipid ultrasound microbubble containing 10-hydroxycamptothecin (10-HCPT), and to assess its targeting function in vitro. Methods After the biotinylated monoclonal antibody Hab18 was prepared, the biotinylated degree was determined. Microbubbles containing 10-HCPT were prepared by mechanical vibration. Then the biotinylated antibody was attached to the surface of the microbubbles by avidin-biotin interaction. The physical property, entrapment efficiency and the drug-loading amounts of 10-HCPT lipid microbubbles were determined. The combination of biotinylated Hab18 with microbubbles containing 10-HCPT was proved by immunofluorescent assay, and the targeting function of the targeted microbubbles containing 10-HCPT was observed with light microscope, served non-targeted microbubbles as control group. Results About 13 biotin molecules were coupled to each antibody in average. The disposition of the prepared microbubbles was steady and the mean diameter was 1.52 μm. The drug entrapment efficiency was 76.32% and the drug-loading amounts was 21.81%. Red fluorescence was observed at the edge of the microbubbles in immunofluorescent assay, and the conjugation of the targeted microbubbles containing 10-HCPT with 7721 cells was tight while control group was negative. Conclusion HCC-targeted lipid ultrasound microbubbles containing 10-HPTC can be prepared successfully, with higher entrapment efficiency and drug-loading amounts and strong targeting function in vitro.

Objective To preparation a kind of Herceptin loaded and breast cancer targeted high molecular polymer ultrasound contrast agent and investigate their affinity for breast cancer in vitro. Methods The high molecular polymer PLGA-COOH ultrasound contrast agents were produced by the double emulsion technique. Herceptin was covalently linked to the PLGA-COOH nanoparticle surface using a carbodiimide technique. Its physical property was determined. The combination of Herceptin with the PLGA-COOH nanoparticle was proved by immunofluorescent assay,and the PLGA-COOH nanoparticle targeting specifity to breast cancer cells was observed with light microscope and confocal microscope,normal PLGA-COOH nanoparticle was served as control group. Results The diameter range of targeted high molecular polymer ultrasound contrast agents was 466.8～857.6 nm, the average diameter was (662.2 ± 69. 7) nm,85.9% of the diameter was in the range. Green punctiform fluorescence was observed by fluorescence microscope,and the conjugation of the targeted high molecular polymer ultrasound contrast agents with MCF-7 cells was tight while the conjugation in control group was negative. Conclusions The Herceptin loaded PLGA-COOH targeted ultrasound contrast agents was prepared successfully. The targeted ultrasound contrast agents can bind to breast cancer effectively in vitro.

Objective To explore the bioeffects of canine myocardium under microbubble destruction via diversity of ultrasonic intension, in order to optimize ultrasonic intension for experiments. Methods Nine mongrel dogs were randomly divided into 3 groups. Ultrasound (1 MHz) in diversity of different intension (0.5 W/cm~2, 1.0 W/cm~2, 2.0 W/cm~2) was applied to expose canine myocardium after intravenous injection microbubbles of 2.0 ml. All the dogs were killed after being exposed for 5 min. The myocardium was harvested for HE staining and observed with transmission electron microscope for the tissue microstructures. Results The myocardium of hyperemia, disfiguration and necrosis wer observed in all groups. Myocardial edema but not hemorrhage appeared with 0.5 W/cm~2 , mild myocardial hemorrhage and slight inflammatory cell infiltration happened with 1.0 W/cm~2, whereas obvious hemorrhage and certain degree of inflammatory cell infiltration occurred with intension of 2.0 W/cm~2. With the augmentation of ultrasonic intension, myocardium trend to aggravate. Conclusion Ultrasound of diversity intension can induce different bioeffects of canine myocardium. Ultrasound mediated microbubble destruction with the intensity of 1.0-2.0 W/cm~2 can provoke a certain degree of inflammatory reaction with mild myocardial damage.