Department of Ultrasound in Medicine, Shanghai Institute of Ultrasound in Medicine, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200233, PR China.
Oncol Rep. 2013 Aug;30(2):842-50. doi: 10.3892/or.2013.2492. Epub 2013 May 23.
It has been shown that 1 and 3 MHz low-intensity ultrasound was able to affect the fragile and leaky angiogenic blood vessels in a tumor. However, the biological effects of 21 kHz low-intensity ultrasound on tumors remain unclear. The aim of the present study was to explore the effects of 21 kHz ultrasound with microbubbles on the regulation of vascular endothelial growth factor (VEGF), cyclooxygenase-2 (COX-2) and apoptosis in subcutaneous prostate tumors in nude mice. The study included three parts, each with 20 tumor-bearing nude mice. Twenty nude mice were divided into four groups: control (sham treatment), microbubble ultrasound contrast agent (UCA), low-frequency ultrasound (US) and US+UCA groups. The UCA used was a microbubble contrast agent (SonoVue). The parameter of ultrasound: 21 kHz, an intensity of 26 mW/cm2, 40% duty cycle (on 2 sec, off 3 sec), 3 min, once every other day for 2 weeks. In the first study, all subcutaneous tumors were examined by contrast-enhanced ultrasonography (CEUS) at the initiation and completion of the experiments. Peak intensity (PI), time to peak intensity (TTP) and area under the curve (AUC) on the time intensity curve (TIC) were analyzed. In the second study, the intensity of VEGF and COX-2 protein expression in the vascular endothelium and cytoplasm was evaluated using immunohistochemistry and laser confocal microscopy. In the third study, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay was used for the evaluation of cell apoptosis in tumor tissues. The tumor cells and vasculature were examined by transmission electron microscopy (TEM). Only in the US+UCA group, PI and AUC decreased. The intensity of COX-2 and VEGF in the US+UCA group in immunohistochemical staining and laser confocal microscopy was lower compared to that of the other three groups. More cell apoptosis was found in the US+UCA group compared to the other 3 groups. In the control, UCA and US groups, the tumors had intact vascular endothelium and vessel lumens in TEM. However, lumen occlusion of vessels was observed in the US+UCA group. Twenty-one kHz low-intensity ultrasound with microbubbles may have anti-angiogenic effects on subcutaneous tumors in nude mice.
已经证明，1MHz 和 3MHz 低强度超声能够影响肿瘤中脆弱和渗漏的血管生成血管。然而，21kHz 低强度超声对肿瘤的生物学效应尚不清楚。本研究旨在探讨 21kHz 超声微泡对裸鼠皮下前列腺肿瘤血管内皮生长因子（VEGF）、环氧化酶-2（COX-2）和细胞凋亡的调节作用。该研究包括三个部分，每个部分都有 20 只荷瘤裸鼠。20 只裸鼠分为 4 组：对照组（假处理）、微泡超声造影剂（UCA）组、低频超声（US）组和 US+UCA 组。所用 UCA 为微泡造影剂（声诺维）。超声参数：21kHz，强度 26mW/cm2，40%占空比（通 2s，断 3s），3min，每隔一天 1 次，共 2 周。在第一项研究中，在实验开始和结束时，所有皮下肿瘤均通过对比增强超声（CEUS）进行检查。分析时间强度曲线（TIC）上的峰值强度（PI）、达峰时间（TTP）和曲线下面积（AUC）。在第二项研究中，通过免疫组织化学和激光共聚焦显微镜评估血管内皮和细胞质中 VEGF 和 COX-2 蛋白表达的强度。在第三项研究中，采用末端脱氧核苷酸转移酶（TdT）介导的 dUTP 缺口末端标记（TUNEL）检测肿瘤组织中细胞凋亡。通过透射电子显微镜（TEM）观察肿瘤细胞和血管。只有在 US+UCA 组，PI 和 AUC 降低。与其他三组相比，US+UCA 组 COX-2 和 VEGF 的免疫组化染色和激光共聚焦显微镜的强度较低。与其他 3 组相比，US+UCA 组发现更多的细胞凋亡。在对照组、UCA 组和 US 组中，TEM 观察到肿瘤血管内皮完整，血管腔通畅。然而，在 US+UCA 组观察到血管腔闭塞。21kHz 低强度超声微泡可能对裸鼠皮下肿瘤具有抗血管生成作用。
