Evaluation of the transport of micromolecular substances through Lymph node

淋巴系统在调节组织和器官的细胞外液和微分子物质的运输中起着重要作用。淋巴液在区域淋巴结之间流动。然而，关于淋巴结内血流的资料很少。在本研究中，我们开发了一种荧光视频显微镜系统，以显示淋巴结内的流动概况，并评估淋巴结的淋巴运输。分离Wistar大鼠的髂淋巴结。将离体淋巴结的进、出淋巴管插管于国产脏器腔内，然后用含荧光示踪剂（fitc -葡聚糖M.W. 71200、φ 1μm羧酸荧光微球和荧光标记淋巴细胞）的Krebs溶液选择性灌注淋巴结。荧光示踪剂在淋巴结内的流动图像由荧光视频显微镜通过SIT-camera和冷冻ccd camera获得，然后将图像记录到录像机。fitc -葡聚糖灌注到淋巴结的传入淋巴管，然后在30sec出现在传出淋巴管改变灌注。另一方面，在灌注20min后，荧光羧酸微球没有出现在传出淋巴管上。灌注20min后，传出淋巴管中也未出现荧光标记的淋巴细胞。微球或淋巴细胞积聚在淋巴结中。这些结果表明，淋巴结内分子大小依赖的淋巴流动途径存在异质性。

The lymphatic system plays an important role in the regulating the transport of extracellular fluids and micromolecular substances in tissues and organs. The lymph travels between the regional lymph nodes. There is, however, few information of the flow profile within lymph nodes. In the present study, we have developed a fluorescent videomicroscopic system to visualize the flow profile within lymph nodes, and evaluate the lymph transport through the lymph nodes.The iliac lymph nodes were isolated from Wistar rats. The afferent and efferent lymph vessels of the isolated lymph nodes were cannulated in a domestic made organ chamber, and then the lymph nodes were selectively perfused with Krebs solution contained fluorescent tracers(FITC-dextran M.W. 71200, fluorescrite carboxylate microsphere φ 1μm and lymphocyte labeled with fluorescence). The flow images of the fluorescent tracers within the lymph node were obtained by a fluorescent videomicroscope via a SIT-camera and a chilled-CCD camera, and then the images were recorded to a video-recorder.The FITC-dextran perfused into the afferent lymph vessel of the lymph node, and then appeared to the efferent lymph vessel alter the perfusion at 30sec. On the other hand, the fluorescence carboxylate microsphere did not appear to the efferent lymph vessel after the perfusion at 20min. The lymphocyte labeled with fluorescence also did not appear to the efferent lymph vessel after the perfusion at 20min. The microspheres or lymphocytes accumulated in the lymph node. These results suggested that there are heterogeneities in the molecular size-dependent lymph flow pathway within the lymph node.