Intra-amniotic LPS amplifies hyperoxia-induced airway hyperreactivity in neonatal rats.

Pediatr Res 2013 Jul 5;74(1):11-8. Epub 2013 Apr 5.

Department of Pediatrics, Seoul National University Bundang Hospital, Seongnam, South Korea.

Background: We previously showed that intra-amniotic lipopolysaccharide (LPS) amplifies alveolar hypoplasia induced by postnatal hyperoxia. We determined whether the priming effect of intra-amniotic LPS amplifies hyperoxia-induced airway hyperreactivity (AHR).

Methods: LPS or normal saline was injected into the amniotic cavities of pregnant rats at the 20th day of gestation. After birth, rat pups were exposed to 60% O₂ or air for 14 d. On postnatal day 14, rat pups underwent forced oscillometry, which included a challenge with nebulized methacholine, and the lungs were harvested for morphological studies.

Results: Hyperoxia significantly increased airway reactivity and decreased compliance. Intra-amniotic LPS further increased hyperoxia-induced AHR but did not further impair respiratory system compliance. Hyperoxia-induced changes in lung parenchymal and small airway morphology were not further altered by intra-amniotic LPS. However, combined exposure to intra-amniotic LPS and hyperoxia increased the proportion of degranulating mast cells in the hilar airways.

Conclusion: Intra-amniotic LPS amplified postnatal hyperoxia-induced AHR. This was associated with increased airway mast cell degranulation, which has previously been linked with hyperoxia-induced AHR. There were no morphologic changes of parenchyma or airways that would account for the LPS augmentation of hyperoxia-induced AHR.

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Source
http://dx.doi.org/10.1038/pr.2013.58DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3707085PMC
July 2013
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