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Early enteral stressors in newborns increase inflammatory cytokine expression in a neonatal necrotizing enterocolitis rat model. Eur J Pediatr Surg 2013 Feb;23(1):39-47 PMID: 23165517 PMCID: PMC5664148

Pubmed ID

23165517

DOI

10.1055/s-0032-1329704

Abstract

INTRODUCTION: Inflammation in the premature intestine is a key factor that leads to the development of necrotizing enterocolitis (NEC). Activation of nuclear factor kappa B (NF-κB) and subsequent inflammation increases the severity of NEC. The aim of this study was to investigate the early temporal expression of inflammatory markers and activation of NF-κB in a neonatal rat model of NEC.

METHODS: Pre- and full-term newborn Sprague-Dawley rat pups were sacrificed at birth, 1.5, 4, 8, and 24 hours after receiving their first feed. Control pups were vaginally delivered and mother fed; NEC was induced by a combination of gavage feeding formula, hypoxia, and enteral lipopolysaccharide (LPS); and formula fed pups were fed every 4 hours with infant formula. Ileal tissue was collected for immunohistochemistry, real-time polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay. Serum was collected for cytokine content. Fold change of expression of inducible nitric oxide synthase (iNOS), interleukin (IL)-1β, IL-6, tumor necrosis factor-α (TNF-α), IL-10, NF-κB p65, and IκBα used RT-PCR. Data were analyzed by paired two-tailed t test, expressed as mean ± standard error of the mean, and p ≤ 0.05 considered significant.

RESULTS: No histologic injury was evident in ileal sections. At 1.5 h, iNOS expression increased twofold over control in NEC pups (2.1 vs. 1.0, p ≤ 0.05) and remained elevated at 24 h (0.7 vs. 9.4, p ≤ 0.05). IL-1β and IL-6 reached a peak at 24 h in NEC tissue compared with control. IL-10 expression rose in NEC pups after 4 h of insult and remained elevated in formula and NEC stressed pups. Coincident with an increase in p65 translocation into the nucleus and a reduction of IκBα detected in the cytoplasm, increased transcription of IκBα occurs.

CONCLUSION: These findings suggest that NF-κB activation initiates inflammation early in the course of NEC resulting in increased proinflammatory protein expression, underscoring the importance of the inflammatory response in this NEC model, which precedes evidence of histological injury.

Author List

Rentea RM, Welak SR, Fredrich K, Donohoe D, Pritchard KA, Oldham KT, Gourlay DM, Liedel JL

Authors

David M. Gourlay MD Chief, Professor in the Surgery department at Medical College of Wisconsin
Keith T. Oldham MD Professor in the Surgery department at Medical College of Wisconsin
Kirkwood A. Pritchard PhD Professor in the Surgery department at Medical College of Wisconsin
Scott R. Welak MD Assistant Professor in the Pediatrics department at Medical College of Wisconsin




Scopus

2-s2.0-84873592351   11 Citations

MESH terms used to index this publication - Major topics in bold

Animals
Biomarkers
Cytokines
Enteral Nutrition
Enterocolitis, Necrotizing
Enzyme-Linked Immunosorbent Assay
Humans
Hypoxia
Ileum
Immunohistochemistry
Infant Formula
Infant, Newborn
Lipopolysaccharides
Nitric Oxide Synthase Type II
Rats
Rats, Sprague-Dawley
Real-Time Polymerase Chain Reaction
Stress, Physiological
Time Factors
Transcription Factor RelA
jenkins-FCD Prod-310 bff9d975ec7f2d302586822146c2801dd4449aad