J Perinat Med. 2013 Nov;41(6):711-8. doi: 10.1515/jpm-2013-0063.
We investigated the combined effects of intra-amniotic lipopolysaccharide (LPS) and maternal betamethasone (BMZ) on alveolarization using a newborn rat model.
LPS (1.0 μg/sac) or vehicle was injected into the amniotic sacs of pregnant rats and BMZ (170 μg/kg) or vehicle was injected intramuscularly into the pregnant rats twice at 8-h intervals on gestation day 20. The rat pups were delivered spontaneously after 2-2.5 days and raised until the measurements were taken. Bronchoalveolar lavage was performed on days 2 and 5, and morphometric analyses of the lungs were performed on days 5 and 14.
Intra-amniotic LPS significantly increased the neutrophils in the bronchoalveolar lavage fluid (BALF) on day 2, but double exposure to LPS and BMZ significantly alleviated the neutrophil increase in the BALF. On day 5, while the neutrophils in the BALF decreased in the animals exposed to LPS alone, the neutrophil numbers in the BALF were steady in the animals exposed to both LPS and BMZ. Morphometric analyses on days 5 and 14 revealed a significant disruption of alveolarization only in the animals exposed to both LPS and BMZ.
Our results suggested that double exposure to maternal BMZ and intra-amniotic LPS induces sustained increase of neutrophils in the lungs and disrupts alveolarization.
我们通过新生大鼠模型研究了羊膜内脂多糖（LPS）和母体倍他米松（BMZ）联合作用对肺泡化的影响。
在妊娠第 20 天，将 LPS（1.0 μg/囊）或载体注入胎鼠羊膜囊内，将 BMZ（170 μg/kg）或载体以 8 小时的间隔两次肌肉内注射给胎鼠。2-2.5 天后，大鼠自然分娩并饲养至测量时。在第 2 天和第 5 天进行支气管肺泡灌洗，在第 5 天和第 14 天进行肺形态计量学分析。
羊膜内 LPS 显著增加了第 2 天支气管肺泡灌洗液（BALF）中的中性粒细胞，但 LPS 和 BMZ 双重暴露显著减轻了 BALF 中中性粒细胞的增加。第 5 天，单独暴露于 LPS 的动物 BALF 中的中性粒细胞减少，但同时暴露于 LPS 和 BMZ 的动物 BALF 中的中性粒细胞数量保持稳定。第 5 天和第 14 天的形态计量学分析显示，仅同时暴露于 LPS 和 BMZ 的动物肺泡化受到显著破坏。
我们的结果表明，母体 BMZ 和羊膜内 LPS 的双重暴露会导致肺部中性粒细胞持续增加，并破坏肺泡化。
