Evaluation of the Combined Effects of Sonodynamic and Photodynamic Therapies in a Colon Carcinoma Tumor Model (CT26)

Document Type: Original Paper

Authors

1 Assistant Professor, Medical Physics Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran

2 Professor, Medical Physics Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran

3 MSc. in Medical Physics, Mashhad University of Medical Sciences, Mashhad, Iran

4 Associate Professor, Pathology Dept, Mashhad University of Medical Sciences, Mashhad, Iran.

5 Assistant Professor, Community Medicine & Public Health Dept., Mashhad University of Medical Sciences, Mashhad, Iran

6 Associate Professor, Pharmaceutical Research Center, Faculty of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran

Abstract

Introduction: Photodynamic therapy is a noninvasive therapeutic method for tumors with a maximum depth of 5 mm. On the other hand, most photosensitizers are also susceptible to ultrasound waves (the basis of sonodynamic therapy). Therefore, it is expected that a combination of the two therapeutic methods will increase effectiveness of photodynamic therapies for lower doses of sensitizer and curing deeper tumors. This study evaluates the synergistic effects of photodynamic and sonodynamic therapies.    
Materials and methods: The study was conducted on a colon carcinoma tumor model in Balb/c mice. The colon carcinoma tumors were induced in the mice by subcutaneous injection. Twenty four hours after intraperitoneal injection of Zinc Phthalocyanine liposome as a sensitizer, at first ultrasound irradiation with a known frequency and intensity was performed followed by illumination of the tumor area. Evaluation of the treatment efficacy was done using daily measurement of the tumors and calculation of their relative volumes. Also, all control groups were considered to confirm the effect of each therapeutic option in the study.  
Results: In the first ten days post treatment, the relative volumes of all groups decreased significantly in comparison with the main control group, but the best response was observed in the photodynamic or sonodynamic therapy groups. The longest doubling time of tumor size was related to groups under photodynamic, sonodynamic and main therapies, and the shortest belonged to the control group.  
Discussion and conclusion: Zinc phthalocyanine liposome is both a photosensitizer and sonsensitizer. Photodynamic and sonodynamic therapies can be efficient in retarding tumor growth rate. In this study, combination of the two methods did not cause improved therapeutic outcomes. It is predicted that this result is related to the choice of therapeutic agents and could be optimized in future.

 

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Volume 6, Issue 3,4
November and December 2009
Pages 29-37
  • Receive Date: 21 April 2008
  • Revise Date: 24 November 2008
  • Accept Date: 21 January 2009