Basic study for sonodynamic therapy to the experimental brain tumor

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We confirmed efficacy of sonodynamic therapy to the experimental brain tumor in the rat. C6 glioma cells were implanted in the brain of Wistcr rat and evaluated efficacy of sonodynamic therapy using a focused ultrasound and Rose Bengal as photosensitizer. A selective anti-tumor effect against cerebral gloma while sparing normal brain tissues was achieved by sonodynamic focused therapy consisting of focused ultrasound at 25 W/cm2 at 1 MHz for 5 min and Rose Bengal, In vitro, C6 rat glioma cells and U251 and U105 human glioma cells were used and evaluated in the efficacy of sonodynamic therapy using parallel ultrasound with photofrin as a photosensitizer Usefulness of low-intensity ultrasound for the cell killing of malignant glioma was confirmed and anti-tumor activity might be enhanced by combination with photofrin, which partially transported by cell surface LRP/ α 2-MR In EM study, swelling of the cytoplasm, plenty of pinocytosis and interruption of the cytoplasmic membrane of the en … More dothelial cells were observed, suggesting-destruction of the blood brain barrier-of the-peritumoral-brain tissue by the sonodynamic therapy. In this experiment, human glioma cells, U251-and U105, differed in sensitivity to the sonodynamic therapy U251 glioma cells survived in the nude rat brain but didn't grow up to neoplastic mass. These cells might differ in proliferation individually, depending upon each animal. U105 glioma cells neither survived in the nude rat brain nor grew up to the mass, so these glioma cells couldn't be used as experimental brain tumor model. We used U87 human glioma cells for experimental brain tumor in the nude rat. These cells were implanted into the nude rat brain-successfully and grew up-to the mass in a week, so U87 human. glioma cells were used for sonodynamic-therapy using the-focused ultrasound. The nude rat brain was exposed and was irradiated by the focused ultrasound after disinfection, A week later, the tumor maximum diameter was compared ultrasound group with control group, 40 mm in average in the former and 38 mm in the latter, therefore, effectiveness of sonodynamic therapy could not be obtained in this model. We speculated that there were any differences of proliferation activity between C6 glioma cells and human glioma cells of U251, U105 and U87 and /or of accumulation rate of photosensitizer to these glioma cells. Less