Figure 7.

Inflammation in the saccular stage human lung down-regulates fibulin-5 expression and alters elastic fiber organization. A–C: Postnatal day (PN) 2 NF-κB–GFP–luciferase (NGL) lung fibroblasts were cultured for 48 hours in serum-free conditions in the presence of tracheal aspirates (TA) from preterm infants with or without exposure to chorioamnionitis. A: Expression of Fbln5 in mouse lung fibroblasts treated with TAs from infants exposed to antenatal inflammation (Chorio TA) compared to control infant TA (CTRL TA). B: Representative immunostaining of elastin in NGL fibroblasts treated with CTRL or Chorio TA and Chorio TA with the addition of adenoviral vector expressing fibulin-5. C: Quantification of the area occupied by the elastin network in immunostained images. Fibroblasts treated with Chorio TA with the addition of adenoviral vector expressing Cre recombinase (CTRL Adv) were also included as controls in these experiments. D: Autopsy lung sections were collected from age-matched stillborn infants (control) or infants exposed to early systemic inflammation because of necrotizing enterocolitis (case) and immunostained for fibulin-5 or stained with Hart's stain for elastic fibers. Images shown are representative photomicrographs of lung sections from a stillborn control and an infant exposed to early systemic inflammation immunostained for fibulin-5 or stained with Hart's stain for elastic fibers. The boxed areas correspond to the images at higher magnification. Data are expressed as means ± SEM. n = 5 per group (A); n = 15 to 20 microscopic fields per group (C). ^∗P < 0.05 (A), versus CTRL TA treatment (C). Original magnification, ×200 (B); ×400 (D, main images); ×600 (D).