Mechanism Investigation of Hypoxia-Inducible Factor in Neonatal Necrotizing Enterocolitis

ZHANG Yunfei, ZHANG Xiao, GUO Chunbao^*

(Department of Hepatobiliary Surgery Children’s Hospital of Chongqing Medical University/National Clinical Research Center for Child Health and Disorders/Ministry of Education Key Laboratory of Child Development and Disorders/ Chongqing Key Laboratory of Pediatrics, Chongqing 400014, China)

Abstract:

This study was to investigate the role of HIF-1α (hypoxia inducible factor-1α) in NEC (neonatal necrotizing enterocolitis) and its possible mechanism. The small intestine tissues of eight children with NEC were collected as the disease group and six children with gastrointestinal abnormalities as the control group. Forty 7-day old C57BL/6 newborn mice were divided into the NEC group (WT/NEC, n=20) and control group (WT/DF, n=20); Forty 7-day-old Grx1 (glutaredoxin1) knockout (Grx1–/–) mice on C57BL/6 background were divided into the NEC group (Grx1–/–/NEC, n=20) and control group (Grx1–/–/DF, n= 20). Western blot was used to detect HIF-1α in human and mouse intestinal tissues. It also detected VEGFA (vascular endothelial growth factor A) in mouse intestinal tissues. Mouse intestinal VEGFA mRNA was detected by qRT-PCR. Immunofluorescence staining was used to detect HIF-1α in intestinal tissue of children and newborn mice. The expression of HIF-1α in the small intestine of NEC children was significantly lower than that in the control group (P<0.05). The expression levels of HIF-1α and VEGFA in the small intestine of WT/NEC mice were significantly lower than those in the WT/DF group (P<0.05). The mRNA expression of VEGFA in WT/NEC mice intestine tissue was significantly lower than that in the WT/DF group (P<0.05), and the expression of VEGFA in the Grx1–/–/NEC group was significantly higher than that in WT/NEC group (P<0.05). HIF-1α was mainly expressed in small intestinal epithelial cells. The immunofluorescence intensity of HIF-1α staining in small intestinal tissues of NEC children and NEC mice was significantly lower than that in the control group, respectively. While Grx1 ablation significantly increased the intensity of HIF-1α immunofluorescence staining in NEC mouse intestine tissue. The results show that HIF-1α plays an important role in NEC children and NEC mice, and its mechanism may be related to the development of intestinal microvascular.