Effect of prenatal heparin-binding epidermal growth factor (HB-EGF) administration on necrotizing enterocolitis-induced lung injury in a murine model.

Abstract

Background: Necrotizing enterocolitis (NEC) is a gastrointestinal emergency in premature neonates. NEC is mediated by toll-like receptor-4 (TLR-4) and associated with lung injury. Previously, we showed that prenatal heparin-binding epidermal growth factor (HB-EGF) administration decreases the incidence of intestinal injury in a rat model of NEC. We tested the hypothesis that prenatally administered HB-EGF would decrease TLR-4 activation and lung injury in a murine model.

Methods: Pregnant mice were given HB-EGF (800 μg/kg/dose) via intraperitoneal injection prior to cesarean section. Pups were exposed to a NEC model and sacrificed on signs of NEC. We collected tissue, performed histological grading of NEC, evaluated alveolar morphometry, and counted TLR-4-expressing cells by immunohistochemistry, unbiased stereology, and quantified TLR-4 protein via ELISA.

Results: Mean alveolar area was significantly different between HB-EGF and control groups compared with NEC only (HB-EGF>NEC; p<0.0001; control>NEC; p=0.0008). Alveolar wall area was significantly decreased in HB-EGF and control groups versus NEC group (p<0.0001). TLR-4-expressing cells were greater in the NEC group versus HB-EGF and control groups (p=0.002). TLR-4 protein was increased in pups exposed to the NEC protocol compared with control (p=0.005 for NEC only; p=0.0004 for HB-EGF treated). There was no difference in TLR-4 protein between HB-EGF and NEC groups.

Conclusions: Our results suggest that prenatal HB-EGF administration preserves lung morphometry and decreases TLR-4 in a murine model of NEC. Possibly, the administration of HB-EGF prenatally to pregnant mothers at risk of delivering a premature infant susceptible to NEC may prevent lung injury.