聚乳酸-羟基乙酸超声造影剂增强兔淋巴结显像的初步实验研究

Effects of poly lacticoglycolic acid ultrasound contrast agent on tumor lymph node imaging

目的 研究自制聚乳酸-羟基乙酸（poly lacticoglycolic acid，PLGA）超声造影剂增强兔肿瘤淋巴结显像的效果及其相关机制。方法采用乳液-溶剂蒸发法制备PLGA超声造影剂；经免大腿皮下注射VX2肿瘤细胞制备肿瘤淋巴结模型，肿瘤细胞生长14～18d后用于超声显像。通过问歇谐波显像观察PLGA造影剂对胭窝肿瘤淋巴结的增强作用，并通过巨噬细胞试验初步探讨增强淋巴结超声显像的相关机制。结果PLGA超声造影剂粒径分布均匀；可以明显增强肿瘤淋巴结显像；细胞试验表明巨噬细胞可以大量吞噬PLGA超声造影剂。结论PLGA超声造影剂是一种良好的肿瘤淋巴结显影剂。淋巴结内巨噬细胞吞噬造影剂后导致造影剂在淋巴结内滞留与聚集可能是其能够明显增强淋巴结显影的机制之一。

Objective To study the effects of poly lacticoglycolic acid（PLGA） ultrasound contrast agent on tumor lymph node imaging and its mechanism. Methods PLGA ultrasound contrast agent was made by double emulsion method; VX2 tumor cells were harvested from carrier rabbits and inoculated in the thigh of healthy New Zealand White rabbits. Implants were allowed to grow for 14 to 18 days before imaging. Popliteal lymph nodes were imaged as the injection sites were massaged. And macrophages were used to investigate the mechanism for lymph node enhancement. Results PLGA ultrasound contrast agent had a tight size distribution. Tumor lymph node was significantly enhanced by PLGA ultrasound contrast agent. Macrophages experiment showed that macrophages could phagocyte lots of PLGA ultrasound contrast agents. Conclusions PLGA ultrasound contrast agent is good for lymph node imaging. The possible mechanism for lymph node enhancement is that macrophages in lymph node can phagocyte lots of PLGA contrast agents, which causes the concentration of PLGA contrast agent in lymph node.