The science and necessity of using animal models in the study of necrotizing enterocolitis.

Necrotizing enterocolitis (NEC) remains one of the highest causes of mortality and of acute and long-term morbidity in premature infants. Multiple factors are involved in the pathophysiology of NEC including the immaturity of the immune system and the complex changing composition of the intestinal microbiome. This is compounded by the fact that the premature infant should ideally still be a developing fetus and has an immature intestinal tract. Because these complexities are beyond the scope of studies in single-cell cultures, animal models are absolutely essential to understand the mechanisms involved in the pathophysiology of NEC and the effects of inflammation on the immature intestinal tract. To this end, investigators have utilized many different species (e.g., rats, mice, rabbits, quails, piglets, and non-human primates) and conditions to develop models of NEC. Each animal has distinct advantages and drawbacks related to its preterm viability, body size, genetic variability, and cost. The choice of animal model is strongly influenced by the scientific question being addressed. While no model perfectly mimics human NEC, each has greatly improved our understanding of disease. Examples of recent discoveries in NEC pathogenesis and prevention underscore the importance of continued animal research in NEC.