Gastric emptying is reduced in experimental NEC and correlates with the severity of intestinal damage

Purpose The aim of this study is to assess gastric emptying in experimental necrotizing enterocolitis (NEC) and its diagnostic significance using non-invasive ultrasound imaging. Methods Fourteen neonatal mice (C57BL/6) were randomized into two groups: NEC [n = 10] and control [n = 4]. NEC was induced by gavage feeding of hyperosmolar formula, hypoxia, and lipopolysaccharide between postnatal day 5 (P5) and 9 (P9). Stomach volume was measured using a 40-MHz ultrasound transducer on P5 and P9. Gastric residual volume was calculated in control mice from two measurements at 4 h interval and in NEC mice from two measurements immediately after gavage feeding and 4 h post-fasting. The distal ileum was harvested for histology and quantitative PCR analysis on P9. Results On P9, NEC mice had a greater gastric residual volume compared to control (p = 0.002) indicating delay in gastric emptying. Positive correlations were found between gastric residual volume and both IL-6 mRNA expression level and histological bowel damage (p = 0.035, p = 0.012, respectively). Conclusions During experimental NEC there is a delay in stomach emptying which is related to the severity of the disease. Ultrasound assessment of gastric emptying is a new non-invasive imaging modality that could be used to predict the severity of NEC.