Experimental studies on risk factors of necrotizing enterocolitis

Introduction. Necrotizing enterocolitis (NEC) is one of the most life-threatening conditions in the neonatal period. This disease is considered to be polyethiological one; however, the pattern of NEC pathogenesis is not clear yet. The aim of the present research is to study in details NEC risk factors and pathogenetic mechanisms in experiment.
Material and methods. NEC was induced in 28 rat pups (breed: Wistar). Newborn animals (21-day gestation age) were labored from three female rats aged 9-12 months. In the research, the experimental animals were induced: hypoxia, inadequate formula feeding and bacterial contamination. The observation period lasted for 96 hours; the obtained results were assessed by the following criteria: clinical symptoms, mortality, intraoperative findings, histological findings and microbiological spectrum.
Results. NEC clinical signs were seen both in subgroup 1A (animals had hypoxia and inadequate formula feeding) and in subgroup 1B (additionally, animals had microbial contamination). Clinical and morphological findings were more pronounced in subgroup 1B. Mortality in subgroup 1B was 50%. The histological picture in subgroup 1A corresponded to that of NEC stage 1A-2A and in subgroup 1B – to NEC stage 2B–3B (by Walsh and Kliegmann). In subgroup 1B, there was a massive intestinal colonization in the intestinal lumen.
Conclusion. Hypoxia and inadequate formula feeding are, as such, risk factors of necrotizing enterocolitis. Additionally, bacterial aggression significantly worsens the course of necrotizing enterocolitis and its prognosis. However, the lack of bacterial component does not rule out NEC onset in newborns.