Abstract

The pathogenetic role of intrauterine infection to the neonatal pulmonary injury and bronchopulmonary dysplasia was assessed by studying the interleukin-6 (IL-6) level in the umbilical cord blood and the early morphologic changes of the neonatal lung. Patients were grouped into bronchopulmonary dysplasia (4 cases), chorioamnionitis without chronic lung injury (4 cases), and 6 cases without morphologic evidence of chronic lung injury or placental inflammation. IL-6 level of umbilical cord blood was higher in babies with bronchopulmonary dysplasia (17.7 pg/ml) compared to those with chorioamnionitis (4.7 pg/ml) or those with morphologically normal lung and placenta (6.2 pg/ml). Morphologic parameters of neonatal pulmonary injury were hyaline membrane, terminal bronchiole inflammation, terminal bronchiole regeneration, alveolar collapse and fibroblastic proliferation. Bronchiolar regeneration was the most peculiar feature seen in the lung with bronchopulmonary dysplasia. Alveolar collapse and interstitial fibroblastic reaction were commonly seen in bronchopulmonary dysplasia. The postnatal age at death was higher in those with bronchopulmonary dysplasia, although the occurrence of the morphologic changes was related with the chronicity of those lesions. These findings suggest that intrauterine infection is an aggravating factor for the neonatal pulmonary injury and bronchopulmonary dysplasia, although the early stage of the lung injury is not a definitive indicator for the progressive pulmonary damage leading to the bronchopulmonary dysplasia.

• Keywords: Bronchopulmonary dysplasia;Hyaline membrane disease;Cytokines;Interleukin-6