title: Validation of protocol of experimental necrotizing enterocolitis in rats and the pitfalls during the procedure.
abstract: OBJECTIVE
  To describe the difficulties of implementing the protocol of experimental necrotizing enterocolitis (NEC) in order to obtain a larger number of newborns affected with the disease and a lower mortality.
  
  
  METHODS
  Term Sprague-Dawley newborns rats (22 days) were divided into four groups of 12 fetuses each (n = 48): EC--breastfed newborns; IH--breastfed newborns and subjected to a stress protocol by ischemia and hypothermia; ESB--formula-fed newborns (Esbilac®, PetAg, Hampshire, IL, USA) and NEC--formula-fed newborns and subjected to stress protocol. The parameters set for the study protocol were: milk concentration (0.19 g ml or 0.34 g/ml), diet instilled volume (according to body weight--200 kcal/day/Kg--or progressive, according to acceptance), weight (gain, loss or maintenance) and duration of the experiment (72 hours or 96 hours). Data of body weight (BW), intestinal weight (IW) and the IW/BW ratio were obtained. Samples of terminal ileum were collected and analyzed by the degree of injury to the intestinal wall. Statistically significance was set to p<0.05.
  
  
  RESULTS
  The established protocol with less mortality and increased number of NEC was with Esbilac® at a concentration of 0.19 g/ml of diet instilled volume of 0.1 ml, every 3 hours, for 72 hours. All infants fed with artificial milk lost weight. In the degree score of intestinal injury, the ESB, IH and NEC groups were considered positive for NEC with greater histological injury in the latter.
  
  
  CONCLUSIONS
  The described NEC protocol in rats allowed a greater survival of puppies with a greater number of animals affected by the disease.
authors: Division of Pediatric Surgery, Department of Surgery and Anatomy, School of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, SP, Brazil.
authors: Frances Lilian Lanhellas
authors: FL
authors: Gonçalves
authors: Rodrigo Melo
authors: RM
authors: Gallindo
authors: Lucas Manoel Mangueira
authors: LM
authors: Soares
authors: Rebeca Lopes
authors: RL
authors: Figueira
authors: Fábio Antônio Perecim
authors: FA
authors: Volpe
authors: Maurício André
authors: MA
authors: Pereira-da-Silva
authors: Lourenço
authors: L
authors: Sbragia
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001942:Breast Feeding; D004195:Disease Models, Animal; D020345:Enterocolitis, Necrotizing / Q000209:etiology / Q000401:mortality; D005260:Female; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley