聚焦超声激活原卟啉Ⅸ对S180肿瘤细胞的杀伤作用

Killing effect on S180 by focused ultrasound activating Protoporphyrin Ⅸ

目的初步研究超声激活原卟啉IX(PPIX)对S180肿瘤细胞的杀伤作用,并探讨其作用的生物学机制。方法采用频率为2·2MHz,强度为3W/cm2的聚焦超声,结合120μmol/L的PPIX作用于S180肿瘤细胞,通过台盼蓝拒染法检测细胞的存活率;扫描电镜观察细胞膜表面超微结构变化;活性氧试剂盒检测细胞悬液中活性氧的生成量;酶化学方法检测细胞内几种抗氧化物酶活性的变化。结果同等条件下,超声结合PPⅨ对细胞的损伤显著高于单纯超声组,而单纯PPⅨ表现出无明显的细胞毒作用;酶化学方法显示,超声激活PPⅨ后细胞内的丙二醛(MDA)含量显著增加,而细胞内的抗氧化物酶类均有不同水平的下降,并且与处理后细胞悬液中活性氧的生成量相关。结论超声激活原卟啉Ⅸ产生的活性氧自由基作用于细胞膜,增加膜脂质过氧化水平,降低细胞内的抗氧化物酶的含量,可能是其损伤S180肿瘤细胞的主要因素之一。

Objective To study porphyrin IX and to explore its the cell killing effect on isolated sarcoma 180 ceils by ultrasound activating Protobiological mechanism. Methods The sonodynamical effect was investigated on S180 tumor ceils exposed to the combination of 120 mol/L protoporphyrin Ⅸ （PPⅨ） and focused ultrasound at the frequency of 2. 2 MHz and an intensity of 3W/cm^2. The livability of ceils was evaluated by trypan blue staining. Scanning electron microscope （SEM） observation of the surface of ceils was performed to evaluate the morphological changes induced by ultrasonic irradiation. The generation of oxygen free radicals in ceil suspensions was immediately detected after treatment by the active oxygen detection kit. Oxidative stress was assessed by measuring the activities of key antioxidant enzymes （ ie, Superoxide dismutase [ SOD ], Glutathione peroxidase [ GSH-PX ], Catalase [ CAT] ） in S180 ceils after SDT. Results The ceil damage rate of ultrasound combined with PPIX was significantly higher than that treated with ultrasound alone only, and PPIX alone had no killing effect on S180 ceils. Enzymatic chemical methods showed the content of MDA significantly increased after treatment, while the activities of key antioxidant enzymes in tumor ceils all decreased at different levels, and was associated to the generation of oxygen free radicals in cell suspension after treatment. Conclusion Oxygen free radical may play an important role in improving the membrane lipid peroxidation, decreasing the activities of key antioxidant enzymes in cells, and the biological mechanism might be involved in mediating the killing effect of S180 cells in SDT.