Fig. 1.

Enterocyte migration is reduced in experimental necrotizing enterocolitis (NEC) and is also inhibited by interferon-γ (IFN), by the inhibition of gap junctions, and by disruption of lipid rafts. A and B: NEC was induced in 10-day-old mice by a combination of formula gavage and hypoxia for 4 days as described in methods, and the terminal ileum was harvested 1 cm proximal to the ileocecal valve. Shown are the terminal ileal histology in control, breast-fed mice (A) and mice with experimental NEC (B). C: expression of IFN in the terminal ileum of two samples obtained from each of mice with and without NEC by RT-PCR; the expression of the housekeeping gene β-actin is shown. D–F: 10-day-old Swiss-Webster mice were induced to develop NEC and injected intraperitoneally with bromodeoxyuridine (BrdU) 18 h prior to euthanasia and immunostained for BrdU (arrows indicate position of peroxidase staining). In control animals, most BrdU has accumulated at varying positions along the villi (D, arrows). In animals with NEC, BrdU uptake remains in the crypts (E), demonstrating a significant impairment in migration. F: rate of migration and percent of maximum crypt height reached are both significantly decreased in NEC compared with controls. Data are means ± SE of 4 separate experiments. *P < 0.05 vs. control. A minimum of 100 cells were counted per experiment. G: rate of migration of IEC-6 cells into a scraped wound in the presence or absence of interferon (IFN), the gap junction inhibitor oleamide (OLM), or upon adenoviral infection and overexpression of dominant negative connexin43 (Cx43; dnCx43), wild-type Cx43 (wtCx43), or the lipid raft inhibitor 2-hydroxypropyl-β-cyclodextrin (HpB). Representative of 4 separate experiments with over 100 cells per experiment counted; *P < 0.05 vs. control; **P < 0.05 vs. dnCx43.