Activation of aryl hydrocarbon receptor by autoinducer-2 alleviates intestinal injury in a neonatal mouse model of necrotizing enterocolitis

Abstract

Objective To investigate the mechanism of autoinducer-2(AI-2) in relieving intestinal injury in neonatal mouse model of necrotizing enterocolitis (NEC). Methods Thirty-six 7-day-old C57BL/6J mice were randomly divided into Control group (fed by mother mice), NEC group (NEC model induced by formula+lipopolysaccharide administration, hypoxia and cold stress), and NEC+AI-2 group (AI-2 solution added to the modeled formula milk), with 12 mice in each group.The body weight and survival rate of each group were recorded during the modeling period.In 3 d after modeling, the mice were euthanized, and the histopathological changes in the terminal ileum were observed using HE staining.The mRNA expression levels of aryl hydrocarbon receptor (AHR), cytochrome P450 1A1(CYP1A1), TNF-α, IL-6 and IL-22 in intestinal tissue were detected with RT-qPCR.The protein levels of AHR and CYP1A1 in intestinal tissues were measured with Western blotting.The contents of TNF-α, IL-6 and IL-22 in intestinal tissues were detected using enzyme-linked immunosorbent assay (ELISA). Results The survival rate of neonatal rats was significantly higher in the NEC+AI-2 group than the NEC group (91.7%vs 66.7%, P < 0.05).The NEC+AI-2 group had obviously lower intestinal pathological injury score (1.33±0.21 vs 2.67±0.33, P < 0.05), increased mRNA and protein levels of AHR and CYP1A1 in intestinal tissues (P < 0.05), decreased expression levels of pro-inflammatory factors TNF-α and IL-6 in intestinal tissues (P < 0.05), while increased expression level of anti-inflammatory factor IL-22(P < 0.05) when compared with the NEC group.Furthermore, the expression and activation of intestinal AHR were negatively correlated with the intestinal pathological injury score (P < 0.001). Conclusion AI-2 alleviates intestinal injury in neonatal mice with NEC by activating AHR to regulate inflammatory response.

Keywords

• aryl hydrocarbon receptor
• autoinducer-2
• necrotizing enterocolitis
• inflammatory response