Keen John A, Hillier Chris, McGorum Bruce C, Bunton David, Nally Jane E
Department of Biological and Biochemical Science, Glasgow Caledonian University, Cowcaddens Road, Glasgow, United Kingdom.
J Pharmacol Toxicol Methods. 2008 Mar-Apr;57(2):92-9. doi: 10.1016/j.vascn.2007.10.005. Epub 2008 Jan 19.
Pharmacological evaluation of the unique equine laminar microvasculature is crucial to understanding its role in health and in diseases such as laminitis. However, separating the distinctive characteristics of arterial versus venous components of this complex vascular network has previously proved to be extremely difficult. Encased in a hard hoof capsule, isolation of individual blood vessels presents a considerable challenge. Exacerbating this difficulty, the laminar venous network is adapted to sustain high intravascular pressures and consequently has thickened walls, making the normally straightforward visual distinction between arteries and veins problematic. Here we describe a novel harvesting and dissection method coupled with a functional analysis procedure that facilitates distinction of arteries and veins.
Laminar tissue was recovered from the hoof of euthanized, clinically normal horses by dissection at the coronary band and stored in cold Krebs-Henseleit physiological salt solution prior to further dissection in the laboratory to remove 2 mm segments of vessels 100-500 microm in diameter. Active length tension measurements were made to evaluate optimal conditions for experimentation, and based on the differences in contractility and appearance, an experimental protocol was set up to allow a) initial distinction between arteries and veins and b) in vitro pharmacological evaluation.
Active length tension studies clearly revealed the presence of two populations of vessels distinguished by either a large or a lower maximal contraction that subsequent histological evaluation confirmed to be arteries and veins respectively. Functional distinction using relative contractility to 60 mM potassium salt solution then demonstrated equine laminar veins to have increased sensitivity to the agonist endothelin 1 (ET-1) compared to arteries.
In vitro evaluation of laminar vessels is possible despite anatomical obstacles. Furthermore, a clear distinction can be made between laminar veins and arteries using functional characteristics providing vessels of a similar size range are selected. Utilising these novel procedures, investigators can unambiguously analyse the pharmacological characteristics of equine laminar veins and arteries to decipher the physiological mechanisms responsible for the control of laminar blood flow.
对独特的马属动物蹄叶微血管系统进行药理学评估，对于理解其在健康状态以及诸如蹄叶炎等疾病中的作用至关重要。然而，此前已证明，要区分这个复杂血管网络中动脉和静脉成分的独特特征极为困难。由于被包裹在坚硬的蹄匣内，分离单个血管面临着巨大挑战。更糟糕的是，蹄叶静脉网络适应于承受较高的血管内压力，因此其壁增厚，使得通常很直观的动脉和静脉之间的视觉区分变得困难。在此，我们描述了一种新颖的采集和解剖方法，并结合功能分析程序，该程序有助于区分动脉和静脉。
通过在冠状带处进行解剖，从安乐死的临床正常马匹的蹄部获取蹄叶组织，并将其保存在冰冷的克雷布斯 - 亨泽莱特生理盐溶液中，然后在实验室进一步解剖，以取出直径为100 - 500微米的2毫米长的血管段。进行主动长度 - 张力测量以评估实验的最佳条件，并基于收缩性和外观的差异，制定了一个实验方案，以实现：a）动脉和静脉之间的初步区分；b）体外药理学评估。
主动长度 - 张力研究清楚地揭示了存在两类血管，其区别在于最大收缩幅度大或小，随后的组织学评估分别证实为动脉和静脉。使用对60 mM钾盐溶液的相对收缩性进行功能区分，结果表明与动脉相比，马属动物蹄叶静脉对激动剂内皮素 - 1（ET - 1）的敏感性增加。
尽管存在解剖学障碍，但仍可对蹄叶血管进行体外评估。此外，如果选择大小范围相似的血管，利用功能特征可以清楚地区分蹄叶静脉和动脉。利用这些新颖的程序，研究人员可以明确分析马属动物蹄叶静脉和动脉的药理学特征，以解读负责控制蹄叶血流的生理机制。
