Aharinejad S, MacDonald I C, MacKay C E, Mason-Savas A
Department of Cell Biology, University of Massachusetts Medical Center, Worcester 01655.
Microsc Res Tech. 1993 Dec 15;26(6):473-88. doi: 10.1002/jemt.1070260602.
We used intravital microscopy of small intestine and pancreas in order to show dynamic interactions between vascular wall and undiluted Mercox, because previous studies of ours have shown that Mercox diluted with monomeric methylmethacrylate penetrates cells in the vascular wall. Scanning and transmission electron microscopy were used to show three-dimensional pathways and correlating tissue structures, which cannot be identified in vivo. The microvascular diameters were not altered when the vasculature was flushed with saline/dextran solution using perfusion pressures between 70 and 140 mm Hg, but, in circumscribed areas, contraction of vascular wall was observed immediately after Mercox injection. This phenomenon was carried out by endothelial cells; pericytes were never present at the site of constrictions. Extravasation, i.e., leakage of the resin into the surrounding tissue, occurred in circumscribed areas regardless of the applied perfusion pressure. The resin also filled routes, which were not perfused with blood before casting. Scanning microscopy of corresponding specimens showed flattened cast channels, with impressions of valves and endothelial cell nuclear imprints characteristic of lymphatics. These results show that undiluted Mercox is a stimulus for vascular cellular components and that it changes the vascular wall permeability, resulting in extravasation and filling of lymphatics. Transmission electron microscopy showed that large vessels were homogeneously filled with resin and that cellular structures were not infiltrated with Mercox. Cut sections of the gold-coated surface of casts showed grooves up to 20 nm wide, suggestive of minimal deformation, while the abluminal surface of the metal film was almost smooth. Another proof of minimal deformation of undiluted Mercox casts is that the diameter of vessels was not altered during and after polymerization. Obtained casts are not fragile, as are casts of diluted Mercox, and phase separation does not occur, which would result in penetration of the cells in the vascular wall. For these reasons, the use of undiluted Mercox is recommended. Mixing 10 ml Mercox with 1 g catalyst resulted in complete polymerization within 5.5-7 min. This mixture can be used for casting biological specimens.
我们利用小肠和胰腺的活体显微镜检查来展示血管壁与未稀释的Mercox之间的动态相互作用，因为我们之前的研究表明，用单体甲基丙烯酸甲酯稀释的Mercox会穿透血管壁中的细胞。扫描电子显微镜和透射电子显微镜用于展示三维路径及相关组织结构，这些在体内无法识别。当使用70至140毫米汞柱的灌注压力用生理盐水/葡聚糖溶液冲洗脉管系统时，微血管直径未改变，但在限定区域，注射Mercox后立即观察到血管壁收缩。这种现象由内皮细胞引起；收缩部位从未出现周细胞。外渗，即树脂漏入周围组织，在限定区域发生，与所施加的灌注压力无关。树脂还填充了铸型前未被血液灌注的路径。相应标本的扫描显微镜检查显示铸型通道变平，有瓣膜印记和淋巴管特有的内皮细胞核印记。这些结果表明，未稀释的Mercox是血管细胞成分的刺激物，它改变血管壁通透性，导致外渗和淋巴管充盈。透射电子显微镜显示大血管均匀地充满树脂，细胞结构未被Mercox浸润。铸型金涂层表面的切片显示出宽度达20纳米的凹槽，提示变形极小，而金属膜的腔外表面几乎光滑。未稀释的Mercox铸型变形极小的另一个证据是，血管直径在聚合过程中和聚合后未改变。所获得的铸型不像稀释Mercox的铸型那样易碎，也不会发生相分离，相分离会导致细胞穿透血管壁。基于这些原因，推荐使用未稀释的Mercox。将10毫升Mercox与1克催化剂混合可在5.5至7分钟内完全聚合。这种混合物可用于铸造生物标本。
