Wideman R F, Forman M F, Hughes J D, Kirby Y K, Marson N, Anthony N B
Department of Poultry Science, University of Arkansas, Fayetteville 72701, USA.
Poult Sci. 1998 Apr;77(4):615-26. doi: 10.1093/ps/77.4.615.
Giant Jungle Fowl previously were shown to be highly resistant to the onset of pulmonary hypertension syndrome (PHS, ascites) under conditions that induce a substantial incidence of PHS in broiler chickens. In the present study, lightly anesthetized, clinically healthy 12- to 13-wk-old male Giant Jungle Fowl maintained a lower respiratory rate, a similar hematocrit, and superior arterial blood gas values when compared with 6-wk-old male broilers. Giant Jungle Fowl weighed less than broilers (1,860 +/- 19 vs 2,788 +/- 63 g, respectively) and had equivalent absolute values for pulmonary arterial pressure, cardiac output, and pulmonary vascular resistance. Acute unilateral pulmonary artery occlusion in Giant Jungle Fowl doubled the pulmonary vascular resistance and forced the right ventricle to propel a sustained 60% increase in blood flow through the vasculature of the unoccluded lung. A transient increase in pulmonary arterial pressure initially was required to overcome the vascular resistance of the unoccluded lung; however, flow-dependent vasodilation gradually reduced the pulmonary vascular resistance and permitted pulmonary arterial pressure to return toward control levels. Unilateral pulmonary artery occlusion also triggered an immediate reduction in the partial pressure of oxygen in arterial blood, and the gradual return of pulmonary arterial pressure toward control levels did not eliminate this ventilation-perfusion mismatch, which has been attributed to blood flowing too rapidly through the unoccluded lung to permit diffusive gas equilibration. The inherent capacity for flow-dependent pulmonary vasodilation may reduce the susceptibility of Giant Jungle Fowl to PHS by reducing the increment in pulmonary arterial pressure required to propel an elevated blood flow through the lungs.
先前的研究表明，在能使肉鸡大量发生肺动脉高压综合征（PHS，腹水症）的条件下，原鸡对该疾病具有高度抗性。在本研究中，与6周龄雄性肉鸡相比，轻度麻醉、临床健康的12至13周龄雄性原鸡维持着较低的呼吸频率、相似的血细胞比容以及更好的动脉血气值。原鸡体重低于肉鸡（分别为1,860±19克和2,788±63克），但其肺动脉压、心输出量和肺血管阻力的绝对值相当。对原鸡进行急性单侧肺动脉闭塞，可使肺血管阻力增加一倍，并迫使右心室推动通过未闭塞肺脏血管系统的血流量持续增加60%。最初需要肺动脉压短暂升高以克服未闭塞肺脏的血管阻力；然而，流量依赖性血管舒张逐渐降低了肺血管阻力，并使肺动脉压恢复至对照水平。单侧肺动脉闭塞还引发动脉血中氧分压立即降低，且肺动脉压逐渐恢复至对照水平并不能消除这种通气-灌注不匹配，这归因于血液流经未闭塞肺脏的速度过快，无法实现气体扩散平衡。流量依赖性肺血管舒张的内在能力可能通过降低推动增加的血流通过肺部所需的肺动脉压升高幅度，降低原鸡对PHS的易感性。
