Scientific Research and Essays

  • Abbreviation: Sci. Res. Essays
  • Language: English
  • ISSN: 1992-2248
  • DOI: 10.5897/SRE
  • Start Year: 2006
  • Published Articles: 2752

Full Length Research Paper

Low-frequency low-intensity ultrasound with contrast agent for the treatment of subcutaneous tumors in mic

  Zhi-Yong Shen1 and Bing Hu2*    
Department of Ultrasound in Medicine, Shanghai Jiaotong University Affiliated Sixth People’s Hospital, Shanghai Institute of Ultrasound in Medicine, Shanghai, 200233, China.
Email: [email protected]

  •  Accepted: 04 October 2011
  •  Published: 09 November 2011

Abstract

 

To determine the effects of ultrasound exposure in the presence of microbubble contrast agent (SonoVue) on the subcutaneous tumor of nude mice. Nude mice bearing subcutaneous tumor were prepared and treated with ultrasound. These animals were divided into three groups: control group (without treatment), low-frequency ultrasound group (US) and low-frequency ultrasound  contrast agent group (US+UCA). UCA was microbubble contrast agent (SonoVue). The tumors were exposed to pulsed ultrasound with a 40% duty cycle and an intensity of 26 MW/cm2 at a frequency of 20 kHz for 3 min using a digital sonifier once every other day for two weeks. The damage to vascular endothelial cells was assessed via transmission electron microscopy (TEM). The protein expressions of VEGF and COX-2 of vessels were detected by Western blot assay. The percentage of tumor shrinkage in US UCA group was higher than US group and down-regulation of VEGF and COX-2 were detected in US  UCA group. After treatment, degeneration of endothelial cells, mitochondrial vacuolation and lumen occlusion were observed in the tumor of US  UCA group. These changes were seldom observed in the US group. Low-frequency ultrasound in the presence of contrast agent may exert therapeutic effect on subcutaneous tumor through destruct of the blood vessels in the tumor.

 

Key words: Ultrasonic biophysics, low-frequency, contrast agent, cavitations, thermal mechanism.