title: [Effects of prenatal steroids in the development of necrotizing enterocolitis in Wistar rat neonates].
abstract: BACKGROUND
  Necrotizing enterocolitis (NEC) is a frequent problem in preterm infants. Prenatal treatment with steroids proved to be effective for lung maturation and it is thought to have a protective effect on the immature bowel.
  
  
  OBJECTIVE
  To study the effects of prenatal treatment with steroids at the onset, clinical course and histological pattern of NEC in an animal model.
  
  
  METHODS
  Pregnant rats received treatment with intraperitoneal hydrocortisone (5 mg/kg) 24 and 48 hrs prior to the expected date of delivery (group S). Control pregnant rats were injected with normal saline, at the same timing (group P). After term delivery by cesarean section, both groups were kept in identical conditions in a neonatal incubator at 35ºC, away from their mothers to prevent any exposure to breast milk. Pups were fed every three hours with neonatal formula via an orogastric tube. To further increase the susceptibility to NEC, pups were exposed to hypoxia followed by hypothermia three times a day for 72 hrs (H-H) or until development of clinical signs of NEC. At that point, each animal was anesthetized and euthanized. The intestine was fixed for histological analysis. Those animals which died before 72 hours were excluded to prevent false positive results in the histopathological exam.
  
  
  RESULTS
  The clinical signs of NEC include oral intolerance, gastric residuals, respiratory distress, abdominal distension, wall erythema and hematochezia; 60% of animals in group P (n= 16) presented with at least one clinical sign, vs. 40% of pups in group S (n= 15). The onset of clinical signs and clinical course in group S was more benign than in group P. Mortality rate was 40% for pups in group P vs. 20% for group S (NS). Histological analysis indicated that 80% of the animals from group P showed signs of NEC, of which 50% reached grade 3-4 (maximum score of damage), whereas only 40% of the animals in group S presented with signs of NEC (p<0.05), all were of grade 0-1 (minimum histological damage).
  
  
  CONCLUSIONS
  Prenatal treatment with steroids was effective for amelioration of the onset and clinical presentation in this model of experimental NEC.
authors.affiliation: Instituto Universitario Escuela de Medicina, Hospital Italiano de Buenos Aires, Argentina.
authors.forename: Laura
authors.initials: L
authors.lastname: Bortolin
authors.forename: Marcelo
authors.initials: M
authors.lastname: Boer
authors.forename: Silvia
authors.initials: S
authors.lastname: Christiansen
authors.forename: Hernán
authors.initials: H
authors.lastname: García Rivello
authors.forename: Julieta
authors.initials: J
authors.lastname: Arbat
authors.forename: Carlos
authors.initials: C
authors.lastname: Fustiñana
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D020345:Enterocolitis, Necrotizing / Q000139:chemically induced*; D005260:Female; D006854:Hydrocortisone / Q000009:adverse effects*; D008431:Maternal-Fetal Exchange; D011247:Pregnancy; D051381:Rats; D017208:Rats, Wistar
chemical_list: D006854:Hydrocortisone