Ultrastructural Studies on Splenic Microcirculation of the Rat

大白鼠脾臟微細循環之超微研究

蘇正堯(C.Y. Su) ； 蔡安一(A.I. Tsai) ； 劉序邦(H.P. Liu) ； 陳麗村(L.T. Chen) ； 錢煦(S. Chien)

《The Chinese Journal of Physiology》 34卷2期 (1991/06) Pp. 223-234

摘要

為了探討脾臟血流路徑以及血管網之立體配置，我們利用血管鑄型法與冷凍劈裂法配合電子顯微鏡（掃描式與穿透式）作觀察，並著重闡釋脾臟過瀘老化或不正常紅血球之機制。研究的結果顯示大白鼠脾臟同時存在開放式及閉鎖式循環方式。穿透式電子顯微鏡亦觀察到下列情形：吞噬細胞(macrophages)往往位於靜脈竇之血管壁外，或兩條靜脈竇之間。有些吞噬細胞伸出偽足，由組織間隙(reticular space)穿過內皮細胞間隙到靜脈竇之管腔內。在閉鎖式循環路徑中，動脈性毛細血管的內皮細胞時常可見不連續處(discontinuity)，紅血球就由此處穿出進入組織間隙內，推測此種路徑可提供流經閉鎖式路徑的紅血球一個替代的循環路線，使其在組織間隙內滯留的時間延長，增加其吞噬細胞接觸之機會。由掃描式電子顯微鏡之觀察亦證實了確有閉鎖式循環路徑的存在。觀察冷凍劈裂之組織，亦觀察到吞噬細胞確有伸出偽足穿出內皮細胞間隙到靜脈竇內的情形。這些超微組織研究顯示大多數的紅血球是經由開放式循環路徑進入組織間隙中，而由吞噬細胞來偵測，將不正常或老化的紅血球過瀘。而那些經過閉鎖式循環路徑的紅血球亦會被攔截，因為部分紅血球會穿出不連續的內皮細胞間隙而進入組織間隙內，或是以相當速度通過靜脈竇腔時，被由組織間隙內穿出偽足的吞噬細胞抓住。這些研究可顯示大白鼠脾臟處理不正常或老化紅血球之機制是多重的。

並列摘要

Su, C.Y., Al. Tsai., H.P. Liu., L.T. Chen, and S. Chien. Ultrastructural studies on splenic microcirculation of the rat. Chinese J. Physiol. 34(2): 224-234, 1991. In an attempt to establish or supplement the three dimensional features of splenic microvasculature, vascular corrosion casts and freeze-cracked tissue blocks of the rat spleen were studied by electron microscopy (SEM & TEM) with special reference on the filtration mechanism of blood cells (RBCs) in the spleen. Both open and closed circulation were observed. TEM investigation showed that macrophages were often found to be located outside the abluminal surface and between two venous sinus branches. Some of them occasionally extend their filopodia and emerge through intercellular slits (IES) out to the luminal surface of the venous sinus. In many cases discontinuity of the junctional complex of the endothelial cells is occasionally identified; this may behave as a detour to prolong RBC passage through the reticular space, thus facilitating their contact with phagocytic cells. SEM observation on vascular corrosion casts have provided clear evidence of direct arteriovenous connection in the rat spleen. Observation on the freeze-cracked tissue block showed a consistent evidence that the macrophages occasionally extend their filopodia and emerge through IES out to the luminal surface of the venous sinus. It indicated that a great majority of the RBCs passing through meshwork of the reticular space of the red pulp, i.e., open circulation would be detected by the macrophages dwelling in the reticular space. The RBCs passing through the fast component. i.e., closed circulation were also subjected to detection and phagocytosis either by macrophages dwelling in the reticular space while their passage through the discontinuity of the junctional complex to the reticular space or by macrophages emerging through IES while their passage along the venous sinus wall. Ultrastructural studies provide an evidence that the spleen performs it flitunctior filtration mechanism.

並列關鍵字

vascular corrosion cast ； freeze-cracking ； macrophages ； intercellular slit ； venous sinus