Changes in surfactant protein gene expression in a neonatal rabbit model of hyperoxia-induced fibrosis

Am J Physiol. 1997 Apr;272(4 Pt 1):L720-30. doi: 10.1152/ajplung.1997.272.4.L720.

Abstract

Lung injuries, including bronchopulmonary dysplasia, alter the surfactant system. We developed a newborn rabbit model of acute, followed by chronic, hyperoxic injury to study surfactant protein (SP) gene expression. Initial litters were exposed to >95% O2 until 50% died (LD50; 7-11 days old). Subsequent litters were exposed to >95% O2 for 8 days, followed by 60% O2 until 22-36 days. Controls were exposed to room air. LD50 animals displayed acute pulmonary inflammation, edema, protein leak, and surfactant dysfunction. These changes resolved, and fibrosis developed by 22 days. Whole lung SP-A mRNA expression (measured by membrane hybridization) was twice control levels at 4 days of >95% O2, with specific elevations in terminal bronchioles and type II cells at 4 days and the LD50 by in situ hybridization. Whole lung SP-B and SP-C mRNA were unchanged from control throughout exposure. However, in situ hybridization showed elevations in SP-B and SP-C mRNA in type II cells in inflamed areas at the LD50. SP mRNA alterations resolved by 22-36 days. The surfactant system recovers from acute hyperoxic injury, despite continued 60% O2 exposure.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acute Disease
  • Animals
  • Animals, Newborn
  • Chronic Disease
  • Gene Expression*
  • Hyperoxia / complications*
  • Hyperoxia / metabolism
  • Hyperoxia / pathology
  • In Situ Hybridization
  • Pulmonary Fibrosis / etiology*
  • Pulmonary Fibrosis / genetics*
  • Pulmonary Surfactants / genetics*
  • RNA, Messenger / metabolism
  • Rabbits

Substances

  • Pulmonary Surfactants
  • RNA, Messenger