Ohtani Osamu, Ohtani Yuko, Carati Colin J, Gannon Bren J
Department of Anatomy, Toyama Medical and Pharmaceutical University, Toyama, Japan.
Arch Histol Cytol. 2003 Aug;66(3):261-72. doi: 10.1679/aohc.66.261.
The aim of the present study was to examine the organization of lymph fluid and cellular pathways and distribution of the membrane water channel Aquaporin-1 (AQP-1) in rat lymph nodes. Lymph fluid and cellular pathways within lymph nodes were examined by fluorescent protein tracer/confocal microscopy and by scanning electron microscopy (SEM), While the distribution of AQP-1 was studied immunohistochemically. Tracer studies showed the subcapsular sinuses continued directly at the hilum or via the intermediate sinuses to the medullary sinuses, and lymphatic labyrinths originating with blind-ends in the deep cortex drained into medullary sinuses. Afferent lymph tracers were also observed in node cortex interstitium. By SEM, lymphatic labyrinths appeared densely filled with lymphocytes and had few intraluminal sinus reticular cells, while medullary sinuses possessed well-developed networks of sinus reticular cells. The presence of many lymphocytes wedged in the walls of the lymphatic labyrinth suggested that lymphocytes migrate between the node parenchyma and lymphatic labyrinths. AQP-1 was distributed on the membrane of lymphatic endothelium and reticular cells as well as on both luminal and abluminal cell membranes of high endothelial venules (HEVs). Our SEM findings support the concept that lymphocytes migrate from the node parenchyma into lymphatic labyrinths in the deep cortex. The nodal distribution of AQP-1 plus the presence of a polarized distribution of ion pumps and/or ion channels in the HEV endothelium hypothesized in our discussion could explain the mechanism of the reported lymph-to-plasma fluid flux in lymph nodes and also facilitate the entry of afferent lymph antigens into the node cortex interstitium.
本研究的目的是检测大鼠淋巴结中淋巴液和细胞通路的组织情况以及膜水通道水通道蛋白-1（AQP-1）的分布。通过荧光蛋白示踪剂/共聚焦显微镜和扫描电子显微镜（SEM）检测淋巴结内的淋巴液和细胞通路，同时采用免疫组织化学方法研究AQP-1的分布。示踪剂研究表明，被膜下窦在淋巴结门处直接延续，或通过中间窦延续至髓窦，起源于深皮质盲端的淋巴迷路引流至髓窦。在淋巴结皮质间质中也观察到传入淋巴示踪剂。通过扫描电子显微镜观察，淋巴迷路内似乎密集充满淋巴细胞，腔内窦网状细胞很少，而髓窦拥有发育良好的窦网状细胞网络。许多淋巴细胞楔入淋巴迷路壁内，这表明淋巴细胞在淋巴结实质和淋巴迷路之间迁移。AQP-1分布于淋巴管内皮细胞和网状细胞的膜上，以及高内皮微静脉（HEV）的管腔和管腔外细胞膜上。我们的扫描电子显微镜研究结果支持这样一种观点，即淋巴细胞从淋巴结实质迁移到深皮质的淋巴迷路中。我们在讨论中假设，AQP-1在淋巴结中的分布加上HEV内皮细胞中离子泵和/或离子通道的极化分布，可能解释了报道的淋巴结中淋巴液向血浆的液体通量机制，也有助于传入淋巴抗原进入淋巴结皮质间质。
