【摘要】 目的 观察低频超声（20 kHz）辐照联合静脉注射微泡造影剂SonoVue对裸鼠前列腺癌（Du145）移植瘤的抑瘤效应，并探讨其可能的抑瘤机制。 方法 通过细胞移植和瘤块移植方法建立24只裸鼠前列腺癌Du145移植瘤模型，随机分为超声微泡组、单纯超声组、单纯微泡组和对照组，每组各6只。超声微泡组：尾静脉注射0.2 mL SonoVue的同时对瘤体行20 kHz超声辐照，辐照强度200 mW/cm2；单纯超声组：尾静脉注射生理盐水0.2 mL，同时超声辐照2 min；单纯微泡组：尾静脉注射SonoVue 0.2 mL同时行假照，各组均隔天1次，共3次，对照组不做任何处理。治疗后测量瘤体大小，绘制瘤体生长曲线，计算抑瘤率。首次治疗后14 d剥离瘤体，通过光学显微镜、电子显微镜观察肿瘤组织病理改变。免疫组织化学方法观察CD34阳性染色血管，计算肿瘤微血管密度（micro vessel density，MVD），比较各组间MVD的差异。 结果 24只裸鼠均成功植瘤。治疗后超声微泡组瘤体体积均数明显小于其他3组（Plt;0.05），抑瘤率为62.7%。光学显微镜下超声微泡组瘤体组织大部分损伤坏死，电子显微镜下超声微泡组肿瘤内微血管的内皮细胞损伤，线粒体肿大，基底膜断裂。超声微泡组瘤体内CD34阳性染色微血管数减少，其MVD值显著低于其他各组。 结论 20 kHz低频超声辐照联合微泡造影剂SonoVue可有效抑制裸鼠人前列腺癌移植瘤的生长，其抑瘤机制可能是通过超声空化效应破坏肿瘤的微血管实现的。【Abstract】 Objective To investigate the anti-tumor effect induced by low-frequency ultrasound (20 kHz) radiation combined with intravenous injection of microbubbles on human prostate carcinoma xenograft in nude mice, and to discuss its probable mechanism. Methods Human prostate carcinoma xenograft model in 24 nude mice were established with human prostate carcinoma Du145 cells inoculation and sub-graft through mice, which were randomly divided into ultrasound+microbubble, ultrasound, microbubble, and control group, with 6 mice in each group. In the ultrasound+microbubble group, 0.2 mL SonoVue was injected intravenously, followed by 20 kHz ultrasound exposure of 200 mW/cm2 at every other day for 3 times totally. Mice in the ultrasound group and the microbubbles group were only treated with ultrasound radiation and microbubbles injection, respectively. The volume of gross tumors was measured, and tumor growth curve was drawn. The ratio of anti-tumor growth was calculated. The mice were sacrificed 14 days after the last ultrasound exposure. Specimens of the exposed tumor tissues were obtained and observed pathologically under light microscope and transmission electron microscope. CD34 positive vessels were counted in all the tumor slices by immunohistochemistry, and the micro-vessels density（MVD）of the tumor was also calculated. Results Du145 prostate tumor model was successfully established in all the mice. The average gross tumor volume of the ultrasound+microbubble group was significant lower compared with the other two groups after treatment (Plt;0.05), and the ratio of anti-tumor growth was 62.7%. Histological examination showed signs cell injury in the ultrasound+microbubble group. Electron microscopic examination revealed that the endothelium of vessels in the tumor was injured. The amount of CD34 positive vessels and MVD of the ultrasound+microbubble group was less than that of the other two groups. Conclusion The low-frequency ultrasound of 20 kHz exposure combined with microbubbles can be used to ablate human prostate carcinoma xenograft in nude mice, which is probably realized through micro-vessels destroyed by cavitation effect of ultrasound.