基于多模态分子影像联合脂质体给药系统的肺癌淋巴系统诊疗一体化研究

Evaluation and treatment of lymphatic metastasis of lung cancer have a vital significance for selection of treatment and prognosis. Many current assessment methods are still not able to exactly explain the status of Lymph node metastasis associated with local tumor to guide doctors in surgery. This research has first been devoted to the design of a multi-functional gold nanoparticle, which is coated with PAMAM dendrimers on the surface, and is connected to various functional groups. The diameter and lipophilic characteristics of this nanoparticle may make it easy to being absorbed into the local lymphoid system and not easy to being absorbed into the blood circulation after interstitial injection; At same time, the multi-modality imaging groups carried by the particles may precisely located tumor-associated region lymph nodes before surgery; the optical imaging groups carried by the particles will guide doctors in surgery to precisely remove the tumor and its associated draining lymph nodes. Then in this study, a liposomal system for drug delivery to the lymphatic system was designed and synthesized, the liposome，which was coated with paclitaxel and gold nanoparticles synthesized in this study, is easy to be absorbed in the local lymphatic system while injected into interstitial ,and is not be easy to access to the blood circulation. The paclitaxel Encapsulated by the liposome can proceed in the killing the residual cancer cells in the lymphatic channels not be removed in surgery. For those patients requiring neoadjuvant chemotherapy, the paclitaxel Encapsulated by the liposome may meanwhile make a local treatment to tumor and its associated lymph node. For those patients who are not suitable for surgery, the paclitaxel Encapsulated by the liposome may simultaneously to facilitate minimally invasive treatment of tumor and its associated lymph node to assist radiotherapy and systemic chemotherapy.

肺癌淋巴转移的评估和治疗是目前国内外研究的热点。目前的许多评估方法仍然不能够在治疗前或手术中精确地说明与局部肿瘤相关的淋巴转移状况以指导医生进行手术切除。我们通过研究，设计了一种以纳米金为核心多功能的纳米颗粒，表面包被PAMAM树状大分子，并连接以各种功能基团。该颗粒所携带的多模态成像基团可在手术前对肿瘤相关区域淋巴结进行精确定位；所携带的光学成像基团将指导医生在手术中精确地切除肿瘤及其相关引流淋巴结。但是其不能满足对转移淋巴结的治疗，因此本研究设计合成了一种脂质体淋巴给药系统，该脂质体包被了紫杉醇及多模态成像的纳米颗粒，其在间质注射后可以对局部肿瘤及淋巴结现象；其所包被的紫杉醇，将对手术中无法切除的残余的淋巴管道内的癌细胞继续进行杀灭；对于需要进行新辅助化疗者，可同时对肿瘤局部及其淋巴转移进行一次手术前局部治疗；对于不能手术者，可以对肿瘤及其淋巴转移同时进行微创治疗以协助全身的放疗

目的：制备多模态分子成像与治疗为一体的多功能紫杉醇脂质体，探讨其表征、物理性质，研究其瘤内注射后在兔肺癌模型体内多模态分子影像、疗效及毒性。方法：采用薄膜分散法制备多功能紫杉醇脂质体，观察其形态，检测平均粒径、包封率、载药率及。构建兔肺癌模型，选取10只分为2组，实验组，制备的多功能脂质体在 CT 引导下经皮穿刺对兔肺癌模型进行瘤内注射2.5～10 μmol /kg；静脉组,静脉给药等量的多功能脂质体；治疗后1,2,4，6，24小时观察药物在兔肺癌模型中的 CT、MR、近红外光谱下的成像。并对兔肺周围淋巴结进行解剖，行银染色实验及Au元素称重。另外选取15只兔肺癌模型，分为三组，实验组： CT 引导下对兔肺癌模型进行瘤内注射2.5～10 μmol /kg；静脉组：静脉给药等量的多功能脂质体；空白组： CT 引导下行瘤内注射等量生理盐水。观察对比肿瘤形态的变化、抗肿瘤效果及毒性。采用单因素方差分析和最小显著差异 ｔ 检验处理数据。结果：成功制备了多功能脂质体，制备的多功能脂质体粒径范围5～200微米，包封率为68 3％，载药率为15．3％。成功构建了兔肺癌模型，多功能脂质体瘤内注射组在 CT、MR、近红外光谱下的成像清晰良好，辨识度高，肿瘤周围淋巴结及淋巴管的CT值、MR信号强度及光学成像信号强度都有所升高，而银染色实验、Au测定结果更进一步的证明了多功能脂质体存在向肺周围淋巴结及淋巴管汇聚现象，多功能脂质体一体化诊疗试验结果，实验组肿瘤大小和重量均低于静脉组和空白组，肿瘤抑制率高于静脉组和空白组。实验组SSTR-2和caspase-3的蛋白水平较高，VEFG组蛋白水平较低。与静脉给药组及空白对照组差异有统计学意义(P<0．05)。毒性测试，肝功、肾功及血项三实验组无明显差异；无统计学意义(P＞0．05)此实验在成像问题上解决了肺癌前哨淋巴结术前精确定位和术中导航问题。在治疗上，可以通过瘤内注射该脂质体，既能治疗局部肿瘤，又能对肺癌前哨淋巴结及淋巴管靶向治疗，且全身毒性较低。本研究为多模态分子影像联合脂质体给药系统的肺癌淋巴系统诊疗一体化诊疗的应用提供研究基础。