Bavis R W, Olson E B, Vidruk E H, Bisgard G E, Mitchell G S
Biology Dept., Bates College, Carnegie Science Bldg., 44 Campus Ave., Lewiston, ME 04240, USA.
J Appl Physiol (1985). 2003 Oct;95(4):1550-9. doi: 10.1152/japplphysiol.01043.2002. Epub 2003 Jun 20.
Developmental hyperoxia (1-4 wk of 60% O2) causes long-lasting impairment of hypoxic phrenic responses in rats. We hypothesized that shorter or less severe hyperoxic exposures would produce similar changes. Hypoxic phrenic responses were measured in 3- to 5-mo-old, urethane-anesthetized rats exposed to 60% O2 for postnatal day 1 or week 1 or to 30% O2 for postnatal week 1. Whereas 1 day of 60% O2 had no lasting effects (P > 0.05 vs. control), both 1 wk of 60% O2 and 1 wk of 30% O2 decreased adult hypoxic phrenic responses (P < 0.05 vs. control), although the effects of 30% O2 were smaller. Hypoxic ventilatory responses (expressed as the ratio of minute ventilation to metabolic CO2 production) were also reduced in unanesthetized rats (5-10 mo old) exposed to 1 wk of 60% O2 during development (P < 0.05). An age-dependent increase toward normal hypoxic phrenic responses was observed in rats exposed to 1 wk of 60% O2 (P < 0.05), suggesting a degree of spontaneous recovery not observed after 1 mo of 60% O2. These data indicate that long-lasting effects of developmental hyperoxia depend on the level and duration of hyperoxic exposure.
发育性高氧（出生后1 - 4周处于60%氧气环境）会导致大鼠对低氧的膈神经反应出现长期损害。我们推测，较短时间或程度较轻的高氧暴露也会产生类似变化。对3至5月龄、经氨基甲酸乙酯麻醉的大鼠进行低氧膈神经反应测量，这些大鼠在出生后第1天或第1周暴露于60%氧气环境，或在出生后第1周暴露于30%氧气环境。虽然出生后1天处于60%氧气环境没有产生持久影响（与对照组相比，P>0.05），但出生后1周处于60%氧气环境和1周处于30%氧气环境均降低了成年大鼠的低氧膈神经反应（与对照组相比，P<0.05），不过30%氧气环境的影响较小。在发育过程中暴露于1周60%氧气环境的未麻醉大鼠（5至10月龄）中，低氧通气反应（以分钟通气量与代谢产生的二氧化碳量之比表示）也有所降低（P<0.05）。在暴露于1周60%氧气环境的大鼠中观察到低氧膈神经反应随年龄增长向正常水平增加（P<0.05），这表明在暴露于60%氧气环境1个月后未观察到的一定程度的自发恢复。这些数据表明，发育性高氧的长期影响取决于高氧暴露的水平和持续时间。
