Stenberg P E, Levin J, Corash L
Department of Laboratory Medicine, University of California School of Medicine, San Francisco.
Exp Hematol. 1990 Feb;18(2):124-32.
We studied thrombopoiesis in mice after the experimental induction of sustained, immune thrombocytopenia with platelet antiserum (PAS). Utilizing light and electron microscopy and a digital image analyzer to determine platelet sectional areas, we examined platelets and megakaryocytes (MK) after 120 h of sustained, severe thrombocytopenia (120CT) and during recovery from thrombocytopenia at 48 h (48R), 72 h (72R), and 120 h (120R) after cessation of administration of PAS. Mean platelet volume (MPV), determined by electrical impedance, also was measured at each time point. Platelets at 120CT (platelet count less than 50,000/microliter), 48R (platelet count 100-200,000/microliter), and 72R (platelet count approximately 1 x 10(6)/microliter) were significantly larger in sectional area than control platelets and contained increased profiles of endoplasmic reticulum and Golgi cisternae, a lower concentration of surface-connected canalicular system, and occasional membrane complexes. The largest median platelet sectional area was detected at 48R and was the largest median value observed in response to either chronic or acute thrombocytopenia. At 120R, most platelets were normal in size and cytoplasmic appearance, although some large cells remained present in the circulation. MPV paralleled the morphometric changes in platelet sectional area. MK were increased in number at 120CT, 48R, 72R, and 120R. In addition, at least half of the MK examined at 48R contained small areas of cytoplasm, devoid of organelles, that were interspersed between larger areas of organelle-filled, undemarcated cytoplasm. The modal bone marrow megakaryocyte ploidy class, determined using two-color fluorescence-activated flow cytometry, shifted from 16N to 32N in response to sustained thrombocytopenia. In contrast, during recovery and development of rebound thrombocytosis, the relative frequency of 8N megakaryocytes was significantly increased. Because there was no consistent correlation between megakaryocyte cytoplasmic characteristics and platelet morphology, these data support the hypothesis that platelet formation is not determined by compartmentalization of MK cytoplasm into platelet areas as MK mature in the bone marrow, but involves a rearrangement of MK cytoplasm immediately prior to platelet release.
我们通过用血小板抗血清（PAS）实验性诱导持续性免疫性血小板减少症，研究了小鼠的血小板生成。利用光学和电子显微镜以及数字图像分析仪来测定血小板截面积，我们在持续性严重血小板减少症（120CT）120小时后以及停止给予PAS后48小时（48R）、72小时（72R）和120小时（120R）从血小板减少症恢复期间，对血小板和巨核细胞（MK）进行了检查。在每个时间点还测量了通过电阻抗测定的平均血小板体积（MPV）。120CT时（血小板计数低于50,000/微升）、48R时（血小板计数100 - 200,000/微升）和72R时（血小板计数约为1×10⁶/微升）的血小板截面积显著大于对照血小板，并且含有增加的内质网和高尔基池轮廓、较低浓度的表面连接小管系统以及偶尔的膜复合物。最大的中位血小板截面积在48R时检测到，并且是在慢性或急性血小板减少症反应中观察到的最大中位值。在120R时，大多数血小板大小和细胞质外观正常，尽管循环中仍存在一些大细胞。MPV与血小板截面积的形态测量变化平行。在120CT、48R、72R和120R时MK数量增加。此外，在48R时检查的至少一半MK含有小面积的无细胞器细胞质，这些细胞质散布在较大面积的充满细胞器的无界限细胞质之间。使用双色荧光激活流式细胞术测定的骨髓巨核细胞倍体模式类别，在持续性血小板减少症反应中从16N转变为32N。相反，在血小板增多症反弹的恢复和发展过程中，8N巨核细胞的相对频率显著增加。由于巨核细胞细胞质特征与血小板形态之间没有一致的相关性，这些数据支持这样的假设，即血小板形成不是由骨髓中巨核细胞成熟时巨核细胞细胞质分隔成血小板区域所决定的，而是涉及血小板释放前巨核细胞细胞质的重新排列。
