Okubo S, Mortola J P
Department of Physiology, McGill University, Montreal, Quebec, Canada.
J Appl Physiol (1985). 1989 Apr;66(4):1772-8. doi: 10.1152/jappl.1989.66.4.1772.
Newborn rats were exposed to 10% O2 from 24 h to 6 days after birth, then returned to normoxia and examined at 50 days of age, i.e., after reaching sexual maturity. Despite the important impairment in somatic growth during hypoxia, at 50 days body weight and nose-tail length were as in control rats never exposed to hypoxia. Hypoxic rats had a bigger chest, with larger anteroposterior diameter, larger surface area of the muscle component of the diaphragm, and heavier and more expanded lungs. None of these structural changes were observed in a third group of rats, which were exposed for 6 days to hypoxia between 35 and 42 days of age, i.e., at a much more advanced stage of postnatal development. In addition, hypoxic rats had higher compliance of the respiratory system and of the lung and lower total pulmonary resistance than control rats. Frequency dependence of compliance was not different. We conclude that in the rat the structural changes induced by neonatal chronic hypoxia are not resolved by the return to normoxia but persist at least until postpuberty with modifications of the mechanical properties of the respiratory system.
新生大鼠在出生后24小时至6天暴露于10%的氧气中，然后恢复至常氧环境，并在50日龄时，即达到性成熟后进行检查。尽管缺氧期间体生长受到严重损害，但50日龄时的体重和鼻尾长度与从未暴露于缺氧环境的对照大鼠相同。缺氧大鼠胸部更大，前后径更大，膈肌肌肉部分的表面积更大，肺更重且扩张更明显。在第三组大鼠中未观察到这些结构变化，这组大鼠在35至42日龄，即出生后发育的更晚期阶段，暴露于缺氧环境6天。此外，与对照大鼠相比，缺氧大鼠呼吸系统和肺的顺应性更高，总肺阻力更低。顺应性的频率依赖性没有差异。我们得出结论，在大鼠中，新生儿慢性缺氧引起的结构变化不会因恢复至常氧环境而消除，而是至少持续到青春期后，同时呼吸系统的力学特性也会发生改变。
