Dextran sodium sulfate (DSS) induces necrotizing enterocolitis-like lesions in neonatal mice

Necrotizing enterocolitis (NEC) is an inflammatory bowel disease of preterm human newborns with yet unresolved etiology. An established neonatal murine model for NEC employs oral administration of lipopolysaccharides (LPS) combined with hypoxia/hypothermia. In adult mice, feeding dextran sodium sulfate (DSS) represents a well-established model for experimental inflammatory bowel disease. Here we investigated the effect of DSS administration on the neonatal murine intestine in comparison with the established NEC model.

3-day-old C57BL/6J mice were either fed formula containing DSS or LPS. LPS treated animals were additionally stressed by hypoxia/hypothermia twice daily. After 72 h, mice were euthanized, their intestinal tissue harvested and analyzed by histology, qRT-PCR and flow cytometry. For comparison, adult C57BL/6J mice were fed with DSS for 8 days and examined likewise. Untreated, age matched animals served as controls.

Adult mice treated with DSS exhibited colonic inflammation with significantly increased Cxcl2 mRNA expression. In contrast, tissue inflammation in neonatal mice treated with DSS or LPS plus hypoxia/hypothermia was present in colon and small intestine as well. Comparative analysis of neonatal mice revealed a significantly increased lesion size and intestinal Cxcl2 mRNA expression after DSS exposure. Whereas LPS administration mainly induced local neutrophil recruitment, DSS treated animals displayed increased monocytes/macrophages infiltration.

Our study demonstrates the potential of DSS to induce NEC-like lesions accompanied by a significant humoral and cellular immune response in the small and large intestine of neonatal mice. The new model therefore represents a good alternative to LPS plus hypoxia/hypothermia administration requiring no additional physical stress.