Sahebjami H, Domino M
Pulmonary Research Laboratory, Veterans Administration Medical Center, Cincinnati, Ohio 45220.
Exp Lung Res. 1989 Dec;15(6):961-73. doi: 10.3109/01902148909069638.
We compared the effects of dexamethasone given to rats from age 4 to 14 days, on alveolar development at age 99 days. Judged by similar nose-to-tail length and body weight, somatic growth was not altered by dexamethasone treatment. Lung volumes in both air- and saline-filled lungs and mean chord length (Lm) were increased, whereas alveolar surface area (Sa) and surface-to-volume ratio (S/V) were diminished in dexamethasone-treated adult rats. These changes were associated with a significant reduction in DNA content and concentration but larger protein/DNA and RNA/DNA ratios in the lungs of treated rats. We conclude that dexamethasone treatment during the critical period of septation in rats impairs alveolar formation, which persists until adulthood and leads to larger and less complex gas-exchange regions. Inhibition of DNA synthesis due to dexamethasone may be responsible for its effects on alveolar development. Larger lung volumes in treated rats are, most likely, related to larger air space dimensions.
我们比较了4至14日龄大鼠给予地塞米松后，对99日龄时肺泡发育的影响。从相似的鼻尾长度和体重判断，地塞米松治疗未改变躯体生长。在地塞米松治疗的成年大鼠中，充气肺和生理盐水填充肺的肺容积以及平均弦长（Lm）均增加，而肺泡表面积（Sa）和表面/容积比（S/V）减小。这些变化与治疗大鼠肺中DNA含量和浓度显著降低但蛋白质/DNA和RNA/DNA比值增大有关。我们得出结论，大鼠分隔关键期给予地塞米松治疗会损害肺泡形成，这种损害持续至成年并导致气体交换区域更大且结构更简单。地塞米松导致的DNA合成抑制可能是其对肺泡发育产生影响的原因。治疗大鼠肺容积增大很可能与气腔尺寸增大有关。
