Suppressive role of vascular endothelial growth factor on intestinal apoptosis in induced necrotizing enterocolitis in rats

PURPOSE: Necrotizing enterocolitis (NEC) is a devastating disease that can cause mortality in preterm babies. NEC may develop through an apoptotic pathway that is known to be inhibited by vascular endothelial growth factor (VEGF). This study determined whether VEGF exerted a protective effect against the development of NEC and apoptosis in rats. METHODS: To determine the effect of VEGF in NEC rats, neonatal rats were randomized into 4 groups: the control group, the NEC group, the NEC + intraperitoneal VEGF (50 ng/kg) group (NEC + VEGF IP group), and the NEC + oral VEGF (50 ng/kg) group (NEC + VEGF OR group). NEC was induced by lipopolysaccharide/hypoxia and cold stress. The animals were sacrificed 72 hours later. After laparotomy, we obtained a region of the proximal small bowel from the ileocecal valve about 18 cm in length. RESULTS: The NEC histological grade, apoptosis histological score, and caspase-3 activity were lower in the NEC + VEGF IP and OR groups than in the NEC group. In the NEC + VEGF IP and OR groups, the messenger RNA expression of apoptotic and inflammatory genes, such as Bax, NF-κB, p53, Fas, FasL, and PAF-R, but not that of Bcl-2, was decreased, as was the Bax/Bcl-2 protein ratio. Histological analysis revealed that the apoptosis-blocking effect of VEGF was more effective in the NEC + VEGF IP group than in the NEC + VEGF OR group. CONCLUSION: We identified apoptotic and inflammatory genes to confirm the preventive effect of VEGF pretreatment on NEC in rats. This study presents a novel approach to prevent apoptosis via VEGF pretreatment in rats with lipopolysaccharide/hypoxia-induced NEC.