Stenberg P E, Beckstead J H, Jackson C W
Department of Pathology, Oregon Health Sciences University, Portland, USA.
Cell Adhes Commun. 1998 Jul;5(5):397-407. doi: 10.3109/15419069809010784.
Wistar Furth (WF) rats have an abnormal thrombopoietic phenotype with morphologically aberrant megakaryocytes, larger than normal mean platelet volume, and platelet alpha-granule protein deficiency. Here, ultrastructural comparisons of WF rat megakaryocytes to those of rats (Wistar) with normal platelet formation during stimulated megakaryocytopoiesis following 5-fluorouracil administration, have revealed a previously unrecognized membrane structure in normal rat megakaryocytes, and two additional abnormalities in WF megakaryocytes. The novel structures were zones of electron density on the cytoplasmic face of apposed plasma membranes of adjoining normal megakaryocytes. These modified focal adhesion-type contacts were distributed at intervals between adjacent megakaryocytes, and were spaced by deposits of extracellular material. These structures also were present between apposed plasma membranes of Wistar rat megakaryocytes in unperturbed marrows, but were absent between megakaryocytes of WF rats. The second WF rat megakaryocyte abnormality is the absence of cytoplasmic dense compartments, another specialized membranous structure that is continuous with the megakaryocyte demarcation membrane system. Both the intercellular plaques and dense compartments of Wistar rat megakaryocytes were found to be rich in cytoskeletal proteins including actin, alpha-actinin, talin, and vinculin as indicated by ultrastructural immunogold labeling. We hypothesize that an abnormality in cytoskeletal protein function may be responsible for the lack of these structures in the WF rat.
Wistar Furth（WF）大鼠具有异常的血小板生成表型，其巨核细胞形态异常，平均血小板体积大于正常，且血小板α颗粒蛋白缺乏。在此，对WF大鼠巨核细胞与5-氟尿嘧啶给药后刺激巨核细胞生成过程中血小板形成正常的大鼠（Wistar）巨核细胞进行超微结构比较，发现正常大鼠巨核细胞中有一种先前未被识别的膜结构，以及WF巨核细胞中的另外两种异常情况。这种新结构是相邻正常巨核细胞并列质膜胞质面的电子密度区。这些修饰的粘着斑样接触点间隔分布于相邻巨核细胞之间，并由细胞外物质沉积物隔开。这些结构在未受干扰的骨髓中Wistar大鼠巨核细胞的并列质膜之间也存在，但在WF大鼠的巨核细胞之间不存在。WF大鼠巨核细胞的第二个异常是缺乏细胞质致密区室，这是另一种与巨核细胞分界膜系统连续的特殊膜结构。超微结构免疫金标记显示，Wistar大鼠巨核细胞的细胞间斑块和致密区室富含包括肌动蛋白、α辅肌动蛋白、踝蛋白和纽蛋白在内的细胞骨架蛋白。我们推测细胞骨架蛋白功能异常可能是WF大鼠缺乏这些结构的原因。
