Longworth K E, Jarvis K A, Tyler W S, Steffey E P, Staub N C
Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis 95616.
Am J Vet Res. 1994 Mar;55(3):382-8.
Seven horses (4 anesthetized and 3 awake) and 2 ponies (anesthetized) were studied to evaluate the high sensitivity of the pulmonary circulation of the horse to various blood-borne particles, and to establish the presence of intravascular macrophages in the lung. Pulmonary and systemic pressures and cardiac output before and during particle injection were measured in some animals. An anesthetized foal had a large increase in pulmonary arterial pressure (32 and 34 mm of Hg) within 1 minute of IV administration of small test doses of radioactively labeled liposomes (2.5 mumol/kg of body weight) or a 1% suspension of blue pigment (0.3 ml/kg), respectively. Quantitative real-time gamma camera imaging of the foal revealed high retention of the labeled liposomes during the first pass through the lungs; retention persisted throughout the experiment. Postmortem analysis revealed 55 and 47% lung retention of liposomes and blue pigment, respectively. The 2 anesthetized ponies had increased pulmonary artery pressure of 34 +/- 7 mm of Hg, decreased cardiac output, and 42% lung retention after administration of 1% blue pigment (0.2 ml/kg), whereas 3 awake horses had increased pressure of 28 +/- 9 mm of Hg after 1.8 x 10(8) (1.8-microns-diameter) latex microspheres/kg. None of the injected particles caused vascular obstruction, and they do not cause pulmonary vascular reactivity in species that lack pulmonary intravascular macrophages. Finally, 3 horses (1 anesthetized and 2 awake) were infused IV with small doses of the blue pigment, and their lungs were perfusion-fixed to identify specific labeling of the pulmonary intravascular macrophages.(ABSTRACT TRUNCATED AT 250 WORDS)
对7匹马（4匹麻醉状态，3匹清醒状态）和2匹小马（麻醉状态）进行了研究，以评估马的肺循环对各种血源颗粒的高敏感性，并确定肺内血管内巨噬细胞的存在。在一些动物中测量了注射颗粒前后的肺循环和体循环压力以及心输出量。一匹麻醉状态的小马在静脉注射小剂量放射性标记脂质体（2.5 μmol/kg体重）或1%蓝色颜料悬浮液（0.3 ml/kg）后的1分钟内，肺动脉压大幅升高（分别为32和34 mmHg）。对这匹小马进行的定量实时γ相机成像显示，标记脂质体在首次通过肺部时高度滞留；整个实验过程中滞留持续存在。尸检分析显示，脂质体和蓝色颜料在肺内的滞留率分别为55%和47%。2匹麻醉状态的小马在注射1%蓝色颜料（0.2 ml/kg）后，肺动脉压升高34±7 mmHg，心输出量降低，肺滞留率为42%，而3匹清醒的马在注射1.8×10⁸个（直径1.8微米）乳胶微球/kg后，压力升高28±9 mmHg。所注射的颗粒均未导致血管阻塞，且在缺乏肺血管内巨噬细胞的物种中不会引起肺血管反应性。最后，对3匹马（1匹麻醉状态，2匹清醒状态）静脉注射小剂量蓝色颜料，并对其肺部进行灌注固定，以识别肺血管内巨噬细胞的特异性标记。（摘要截短至250字）
