【Animal Modeling】- Improvement and evaluation of the method for establishing the neonatal rat model of necrotizing enterocolitis

  Objective To identify a simple and effective NEC modeling method by improving and comparing the commonly used animal models of necrotizing enterocolitis at home and abroad.

  Methods Newborn SD rats within 2 hours of birth were randomly divided into 5 groups, 10 rats in the control group, and 20 rats in the experimental group. Group A and surrogate mother mice were fed with milk in the same cage without any intervention; group B was artificially fed + hypoxic cold stimulation + (lipopolysaccharide) LPS gavage (5 mg/kg body weight); group C was artificially fed + hypoxia Cold stimulation + LPS gavage (10 mg/kg); group D artificial feeding + hypoxia cold stimulation + LPS intraperitoneal injection (2 mg/kg); E group artificial feeding + hypoxia cold stimulation + LPS intraperitoneal injection (5 mg/kg). The activity and body weight of the newborn mice were observed daily. After the experiment, the small intestine tissue was taken for hematoxylin-eosin staining to evaluate the degree of intestinal pathological damage; the level of tumor necrosis factor a (TNF-α) in the small intestine tissue was detected.

  RESULTS: The neonatal mice in the experimental group had different degrees of decreased activity, abdominal distension, diarrhea, black stools, and weight loss. The pathological score showed that the pathological damage score of the neonatal mice in the experimental group was significantly higher than that in the control group (P<0.05). The LPS intraperitoneal injection group (D, E) had a higher incidence of NEC than the oral administration group (B, C) (P<0.05). The mortality rate was significantly higher (P<0.05).

  Conclusion The method of establishing NEC on the basis of artificial feeding and hypoxia cold stimulation combined with intraperitoneal injection of low-dose LPS (2 mg/kg) is more operable and stable.