Basic research to sonodynamic therapy for the brain tumor

为了明确声动力学治疗对脑胶质瘤耐药细胞的存在，阐明声动力学治疗对脑胶质瘤耐药的机制，我们对两种不同的脑胶质瘤细胞进行了α 2 MR/LRP的研究。声动力治疗对出现α 2 MR/LRP的U251 MG细胞有明显的杀伤作用，对U105 MG细胞有一定的强化作用。RAP阻断α 2 MR/LRP结合后，对U251 MG细胞的杀伤作用受到抑制。U251 MG细胞有α 2 MR/LRP表现，瘤细胞形态改变明显，而U105 MG细胞无α 2 MR/LRP表现，瘤细胞形态改变不明显。我们认为，α 2 MR/LRP的存在参与了声动力疗法的治疗敏感性，我们用电镜研究了声动力疗法对血脑屏障的影响。在大鼠脑中，在基底神经节内产生局部病变，峰值局灶强度为100 W/cm 2，超声时间为3分钟，给予虎红作为光敏剂。电镜下可见血管周围细胞变性，树突和内皮细胞肿胀。在内皮细胞的细胞质中，观察到线粒体肿胀，大量的胞饮小泡和内皮细胞膜的破坏。这些现象在中心区域而非外周区域更为突出，并且在虎红给药后更为严重。这些结果表明，血脑屏障通透性的增加是由于内皮细胞膜的破坏和胞浆的胞饮小泡的增加，而不是紧密连接的开放。

We investigated two different kinds of glioma cells which were different in manifestation of α 2MR/LRP in order to make clear presence of tumor cells brain tumor resistant to sonodynamic therapy and to clarify the mechanism of tolerance to the ultrasound. Cytocidal effect by sonodynamic therapy was meaningful in the U251MG cell that α 2MR/LRP appeared, and there were a little reinforcement effects in an U105MG cell. Cytocidal effect in U251MG cells was restrained by interrupting the combination of α 2MR/LRP by RAP. The form change of a tumor cell was remarkable in the U251MG cell with manifestation of α 2MR/LRP and was poor in an U105MG cell without 2MR/LRP. We thought that these results showed that presence of α 2MR/LRP participated in treatment sensitivity of sonodynamic therapy.We studied to clarify the influence to the blood brain barrier on sonodynamic therapy using an electron microscopy. In the rat brain, localized lesions were produced within the basal ganglia with peak focal intensity of 100 W/cm2 and sonic time of 3 minutes and Rose Bengal was administrated as a photosensitizer. Electron microscopic examination showed degenerated cells at the perivascular space, and swelling of dendrites and endothelial cells. In the cytoplasm of the endothelial cells, swelling of mitochondria, a large number of pinocytic vesicles and disruption of endothelial cell membranes were observed. These phenomena were more prominent at the central area rather than peripheral area, and were more intense with Rose Bengal administration. These findings suggest that the increase of permeability of blood brain barrier occurs due to disruption of endothelial cell membrane and the increase of pinocytic vesicles of the cytoplasm rather than the opening of tight junction.