Aharinejad S, Marks S C, Böck P, MacKay C A, Larson E K, Tahamtani A, Mason-Savas A, Firbas W
First Department of Anatomy, University of Vienna, Austria.
Anat Rec. 1995 May;242(1):111-22. doi: 10.1002/ar.1092420115.
Little is known about the three-dimensional micromorphology of vessels in the growth zone of long bones, where significant vasculogenesis occurs. Therefore, we examined the microvascular pattern of the femoral metaphysis.
Six-week-old normal rats of either sex were used. We cast the femurs of 14 rats with Mercox for scanning electron microscopy (SEM), and in 10 rats we prepared tissue sections of femurs for light (LM) and transmission electron microscopy (TEM).
In the LM, calcified cartilage was found to define cylindrical compartments beneath the last row of hypertrophied chondrocytes of the metaphyseal growth plate. These compartments ran in the bone's longitudinal axis and contained a single capillary profile. Endothelial cells of these capillaries often showed increased cytoplasmic volume and loose texture of nuclear chromatin. Cast metaphyses by SEM showed numerous parallel vascular loops with nodular protrusions 10-12 microns in diameter at their tips. The loops had ascending and descending limbs with a luminal diameter of 10-14 microns. Small projections 4-5 microns in diameter and delicate crests were sometimes found on the tip of the larger nodes. In a 100 x 100 microns area, there were 14-17 large nodes. By TEM, capillary sprouts were identified at the level beneath the last row of hypertrophied chondrocytes. These capillaries had voluminous endothelial cells rich in free ribosomes and rough endoplasmic reticulum. Endothelial cell nuclei were rounded and showed loose chromatin texture. Endothelial cells were connected by intermediate junctions and there was no basal lamina. Deeper into the metaphysis, arterioles and sinusoids were present.
We conclude that the metaphyseal plate of the growing rat offers an optimal model to study vasculogenesis. Capillary sprouts can be readily identified, measured, and counted because they are located within a plane bordering against avascular cartilage. In addition, by using microvascular corrosion casting in SEM not only capillary sprouting per se but also different stages of neovascularization, indicated by differently sized nodular projections at the tip of vascular loops, can be studied in the growing long bone.
在长骨生长区发生显著血管生成的部位，关于血管的三维微观形态学所知甚少。因此，我们研究了股骨近端骨骺的微血管模式。
使用六周龄的正常雌雄大鼠。我们用甲基丙烯酸甲酯对14只大鼠的股骨进行铸型以用于扫描电子显微镜（SEM）观察，对10只大鼠的股骨制备组织切片用于光学显微镜（LM）和透射电子显微镜（TEM）观察。
在光学显微镜下，发现钙化软骨在干骺端生长板最后一排肥大软骨细胞下方界定出圆柱形区域。这些区域沿骨的纵轴排列，且每个区域包含单个毛细血管轮廓。这些毛细血管的内皮细胞常表现出胞质体积增大和核染色质质地疏松。通过扫描电子显微镜观察铸型的干骺端，可见许多平行的血管袢，其尖端有直径为10 - 12微米的结节状突起。这些血管袢有上升和下降的分支，管腔直径为10 - 14微米。在较大结节的尖端有时可见直径为4 - 5微米的小突起和纤细的嵴。在100×100微米的区域内，有14 - 17个大结节。通过透射电子显微镜观察，在最后一排肥大软骨细胞下方的层面可识别出毛细血管芽。这些毛细血管有丰富的内皮细胞，富含游离核糖体和粗面内质网。内皮细胞核呈圆形，染色质质地疏松。内皮细胞通过中间连接相连，且无基膜。在干骺端更深处，存在小动脉和血窦。
我们得出结论，生长中大鼠的干骺端板为研究血管生成提供了一个理想模型。毛细血管芽易于识别、测量和计数，因为它们位于与无血管软骨相邻的平面内。此外，通过在扫描电子显微镜中使用微血管铸型技术，不仅可以研究毛细血管芽本身，还可以研究生长中的长骨中血管袢尖端不同大小的结节状突起所指示的新生血管形成的不同阶段。
