Bernard S L, Luchtel D L, Glenny R W, Lakshminarayan S
Department of Pulmonary and Critical Care Medicine, University of Washington School of Medicine, Seattle, USA.
Respir Physiol. 1996 Aug;105(1-2):77-83. doi: 10.1016/0034-5687(96)00027-8.
This study characterizes the existence of a bronchial circulation in a marsupial, an animal which does not undergo placental development and does not have a ductus arteriosus. Direct perfusion of the lung by the pulmonary vasculature during the fetal development of opossums may occur, potentially eliminating the need for a bronchial circulation. We used radio- and fluorescent-labeled microspheres in conjunction with postmortem intravascular casting to determine if opossums have a systemic (bronchial) blood supply to the lung (n = 9). Gross postmortem examination of the intravascular casts showed a well-developed common bronchial artery. The histological distribution pattern of fluorescent microspheres was primarily to the airways. A few fluorescent microspheres were observed in the alveolar capillaries, indicating that a precapillary bronchial-to-pulmonary anastomosis exists in the opossum. Using the reference flow technique, total bronchial blood flow to the left lung averaged 0.95 +/- 0.58 SE ml/min. The presence of a bronchial circulation in the opossum suggests that it is more than a vestigial structure from embryonic development, potentially supporting its functional importance for carrying nutrients to the airway.
本研究描述了有袋动物支气管循环的存在，有袋动物是一种不经历胎盘发育且没有动脉导管的动物。在负鼠胎儿发育过程中，肺可能由肺血管系统直接灌注，这可能消除了对支气管循环的需求。我们使用放射性和荧光标记的微球结合死后血管铸型技术来确定负鼠是否有肺的体循环（支气管）血液供应（n = 9）。血管铸型的大体尸检显示有一条发育良好的总支气管动脉。荧光微球的组织学分布模式主要是在气道。在肺泡毛细血管中观察到一些荧光微球，表明负鼠存在毛细血管前支气管到肺的吻合。使用参考流量技术，左肺的总支气管血流量平均为0.95±0.58 SE毫升/分钟。负鼠中支气管循环的存在表明它不仅仅是胚胎发育遗留的结构，可能支持其对气道输送营养物质的功能重要性。
