【作者】 熊兰；

【导师】 孙才新；

【作者基本信息】 重庆大学 ， 电气工程， 2004， 博士

【摘要】 癌症是威胁人类生命的主要疾病，人们对肿瘤疗法的研究不仅限于对肿瘤组织的杀伤和抑制作用，在抗肿瘤血管效应、淋巴管效应、免疫效应和诱导凋亡效应等方面也开展着深入的研究。 陡脉冲疗法是本课题组开创的一种新的癌症物理治疗方法，在大量的离体、细胞和动物实验中已证实对肿瘤组织的有效杀伤和抑制作用。本文完成了上述四大效应的实验研究，观察到：(1)陡脉冲可破坏肿瘤营养血管和毛细淋巴管，使其栓塞、凝固性坏死，并下调血管内皮细胞生长因子VEGF-A和促淋巴管再生因子VEGF-C的水平，具有抗血管和淋巴管再生的作用，从而减少了残留、存活的肿瘤细胞经淋巴管途径转移到其他部位的可能性，防止肿瘤增生和转移。(2)陡脉冲能明显增强大鼠脾淋巴细胞的增殖反应和NK细胞的活性。具有活化巨噬细胞，增强其细胞毒功能并促进其分泌白细胞介素IL-4、IFN-γ和肿瘤坏死因子TNF-α的作用。导致脾淋巴细胞产生细胞因子的活性增强，诱导荷瘤宿主体内的免疫应答，有助于提高机体的免疫功能。(3)陡脉冲能抑制细胞增殖，改变细胞周期，下调Bcl-2／Bax表达的比值，造成细胞器内促凋亡因子的释放，诱导细胞凋亡。 同时，本文深入分析陡脉冲对肿瘤细胞的杀伤和诱导凋亡的机制。(1) 借助ANASYS电磁场分析软件，用有限元方法仿真计算陡脉冲在均匀介质中的电场强度分布，并与大白兔肝脏实验相结合，确定能有效杀伤肿瘤组织的电极尺寸和间距、阵列布置方式、脉冲峰值等因素，寻找兔肝组织不可逆性电击穿的电场强度阈值，最终有效控制陡脉冲的杀伤范围，实现最佳疗效。(2) 建立单细胞模型，推导陡脉冲电场作用下单细胞极点处的跨膜电位，明确跨膜电位按指数衰减的变化规律；分析了脉冲宽度与跨膜电位的关系，以及电穿孔过程中细胞膜电导率和细胞结构变化对跨膜电位的影响，分析陡脉冲导致细胞不可逆性电击穿的机制。(3) 通过傅立叶频谱分析，推证陡脉冲波形的选择依据。证实陡脉冲强化超高频效应，有可能诱导细胞凋亡，从而防止细胞膜破损后细胞器游离，引起肿瘤转移或复发；而且脉宽越窄，超高频杀伤效应越强，为脉冲特征参数的选择提供依据。更多还原

【Abstract】 Cancer is the main disease which has been threatening human life, dozens of malignant tumor therapies come forth with their own dominance and deficiency. Today, the research is not limit to their cytocidal and inhibitory effect on tumor cell, but the anti-tumor effect on vessel, lymphatic, immunity system and apoptosis abduction.Steep pulse therapy (SPT) is a new physical therapy initiated by us. In forepassed experiments in cell line, BALB/c mice and tumor in vitro, we confirmed adequately its cytocidal and inhibitory effect on tumor cell. In this paper, experimental studies were developed from these four anti-tumor effects, they become conscious as follows: (1) Under the steep pulse field, tiny blood and lymphatic vessels were jammed or destroyed, the expression of VEGF-A and VEGF-C was descent, those mean that SPT can detain rudimental tumor cell transferring to other part by the way of blood and lymphatic vessel, and prevent tumor from proliferation and transfer. (2 )SPT can the proliferation of spleen lymphatic cell, arouse the activity of NK cell and huge-spit cell, enlarge latter secretion of IL-4 IFN and TNF-and then strengthen immunity function of organism (3) SPT can prohibit cellular proliferation, change cellular cycle, and induce cellular apoptosis by descending the expression ratio of Bcl-2/Bax to release the apoptosis factors,.Moreover, this paper analyses SPT’s mechanism in killing tumor cell and inducing cellular apoptosis. (1) With ANASYS electromagnetic field analysis software and finite element method (FEM), electric field intensity (EFI) distribution in symmetrical medium is calculated. Combined with rabbit liver experiment, we find the relationship between electrode size distance between different electrode and electrode array arrangement and killing efficiency, select the EFI threshold leading liver cell to irreversible breakdown. (2) Single cell model is built to calculate the transmembrane potentials(TMP) in polar points. TMP curve follows exponential attenuation rule, the more narrow pulse width is, the faster attenuation pace is. During the electroporation, membrane conductivity raises, cellular radius prolongs, membrane thickness is thinner, because of these change, ascend time of TMP is shortened and attenuation pace slows down. (3) Compared with square pulse, SPT owns the more superior ultra high frequency (VHF) killing effect on organelle after frequency spectrum analysis, which means that SPT can induce cellular apoptosis, prevent organelle drifting away from destroyed membrane, stop the tumor transferring or recurring. The more narrow pulse width is, the higher killing effect of VHF part is. With these results, we can control freely the killing effect of SPT in proper scope with the best curative effect.更多还原