The effects of prenatal infection on the lung development of rat pups / 国际儿科学杂志

ABSTRACT

Objective To explore the effects of prenatal infection on the development of lungs by dynamic observation of morphology and numbers of inflammatory cells in lungs of rat pups exposed to antenatal inflammation.Methods Pregnant Wistar rats were randomly divided into experimental group and control group.Pregnant rats of both groups were intraperitoneal injected with either lipopolysaccharide (LPS) 2.5mg/kg or the same volume of normal saline on embryonic day 19 and 20, respectively, and were allowed to term deliver.Onday1, 3, 7, 14, 21and28 (D1, D3, D7, D14, D21 andD28), eight pups of each group were killed by 10％ chloral hydrate (1ml/kg) and lungs were collected.The numbers of myeloperoxidase (MPO) and CD68 as markers of both neutrophils and macrophages were counted.Morphometric assessments were performed by measuring the mean numbers of alveolar, the mean ratio of alveolar surface area to per tissue and the mean thickness of alveolar septum.Results With the increasing of postnatal days, the mean numbers of alveolar and the mean ratio of alveolar surface area to per tissue in both groups increased.The mean thickness of alveolar septum got thinner and the numbers of inflammatory cells decreased.On D1, D3, D7 and D14, the mean alveolar numbers of the experimental group (88, 89, 102 and 127 /mm2) were significantly less than those of the control group (105, 109, 123, 156/mm2), P =0.024, 0.009, 0.013, 0.004, respectively.On D1, D3 and D7, the mean ratios of alveolar surface area to per tissue were significantly larger (0.552,0.603 and0.533) than those of control group (0.478, 0.485 and 0.404), P=0.003, 0.001, 0.000, respectively.On D1 and D3, the alveolar septum thickness was significantly thinner (12.30 and 10.75 μm) thanthatin control group (17.13 and 16.13 μm), P=0.000, 0.000, respectively.On D1, D3, D7 and D14, the mean numbers of neutrophils of the experimental group (681, 582, 393 and 379/mm2) were significantly more than those of control group (164, 211, 145 and 179 /mm2), P =0.000, 0.000, 0.000,0.003, respectively.On D1, D3 and D7, the mean numbers of macrophages (613, 578 and 337 /mm2)were significantly more than those of control group (170, 182 and 127, /mm2) , P=0.000, 0.000, 0.000,respectively.Conclusion Prenatal infection results in larger and fewer alveolars and more inflammatory cells in lungs of rat pups.With the increasing of postnatal days, the alveolar morphology was similar to the controis.