|Journal||Cancer Chemotherapy and Pharmacology|
|Publisher||Springer Berlin / Heidelberg|
|ISSN||0344-5704 (Print) 1432-0843 (Online)|
|Issue||Volume 60, Number 5 / October, 2007|
|Subject Collection||Biomedical and Life Sciences|
|SpringerLink Date||Friday, January 12, 2007|
|(1)||College of Life Sciences, Shaanxi Normal University, Xi’an, 710062, China|
Received: 14 October 2006 Accepted: 21 December 2006 Published online: 12 January 2007
The sonodynamically induced anti-tumor effect of PPIX was studied in mice bearing S180 solid tumors. In order to determine the optimum timing of ultrasound exposure after administration of PPIX, the PPIX concentrations in plasma, skin, muscle and tumor were determined by the fluorescence intensity of tissue extractions with a fluorescence spectrophotometer based on the standard curve. Anti-tumor effects were estimated by measuring the tumor size and the tumor weight. Additionally, the morphological changes of S180 cells were evaluated by transmission electron microscope (TEM) observation immediately after sonodynamic therapy (SDT) treatment.
A time of 24 h after the intravenous administration of PPIX was chosen as the best time for ultrasound exposure. The antitumor effect induced by PPIX mediated sonodynamic therapy (PPIX-SDT) was in a dose dependent manner when ultrasound intensity was at or above the inertial cavitation threshold (5 W/cm2). A significant tumor growth delay was observed both in PPIX mediated sonodynamic therapy and in Hp mediated sonodynamic therapy treatments (Hp-SDT), and the tumor weight inhibition ratios after the synergistic treatments were 42.82 ± 0.03 and 35.22 ± 0.03%, respectively, this difference was significant at P <>2) showed a slight tumor growth inhibitory effect compared with the control group, and PPIX or Hp alone showed almost no significant effect. Furthermore, TEM observation indicated cell damage was more serious in PPIX-SDT treatment group than in Hp-SDT treatment group. After sonication, the cell ultra-structure such as cell membrane destruction, mitochondria swelling, chromatin condensation might be important factors that inhibited the tumor growth and even induced cell death.
Keywords Sonodynamic therapy - Anti-tumor effect - Protoporphyrin IX - Hematoporphyrin - Sarcoma 180