Animal model of necrotizing small bowel conjunctivitis in neonates

Summary

Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency in neonates, especially in preterm infants, with a high incidence and mortality rate, and difficult to treat. It is believed that preterm birth, hypoxia and asphyxia, and infection are the risk factors for the development of NEC. Neonatal rats were selected and given an animal model of necrotizing enterocolitis based on the above independent risk factors.

Principle

The pathogenesis of NEC is often not a single factor, but a combination of ventricular hypoxia infection after preterm delivery and improper feeding. Therefore, according to the characteristics of NEC pathogenesis, we selected neonatal SD rats and used the modeling method of "artificial feeding + hypoxic reoxygenation cold stimulation + LPS" as a three-factor intervention, which is closer to the clinical characteristics of NEC pathogenesis.

Appliance

The new animal model established in this study integrates multiple pathogenic risk factors such as preterm birth, low birth weight, asphyxia, hypoxia, ischemia-reperfusion injury, rapid overfeeding, and intestinal pathogenic bacterial infections, which is more consistent with the pathophysiological mechanism of NEC, and it is a more ideal animal model for the study of necrotizing small-break colitis in newborn infants, and it is significantly better than the other methods at home and abroad.

Operation method

Establishment of an animal model of necrotizing small bowel conjunctivitis

Principle

According to the characteristics of NEC pathogenesis, the neonatal SD rats were selected, and the three-factor modeling method of "artificial feeding, hypoxic reoxygenation cold stimulation, and LPS" was used, which is closer to the clinical characteristics of NEC pathogenesis.

Materials and Instruments

Animal model:
Neonatal SD rat.
Equipment:
Silicone tube.
Reagents:
①75% medical ethanol;
② Alcohol;
③ Saline;
④LPS.

Move

The steps for the establishment of the animal model of necrotizing small intestinal conjunctivitis were as follows:

(I) Experimental animals and treatment: A

. Newborn SD rats were separated from their mothers on the day of birth and placed in a neonatal rat nursery for artificial feeding

.

B. Clean and sterile 1.9 F silicone tubes were inserted orally every 4 hours, and the skin around the oral cavity of newborn rats was cleaned with saline and 75% medical ethanol before feeding.

C. Immediately after feeding, the silicone tube should be cleaned and sterilized, and then soaked in a closed container of 75% medical ethanol for spare use, and then taken out and washed thoroughly with sterilized saline before the next use. Each silicone tube should be sterilized and used only for 1 newborn rat.

D. The first feeding volume is 0.1 mL, and then increase by 0.1-0.3 mL every 24 hours.

(B) Hypoxia reoxygenation cold stimulation: A

. (1) After the oxygen meter was zeroed, the probe was connected to the notch at the top of the closed hypoxia box, closed by adhesive tape, and pure nitrogen was filled into the air inlet hole, and the flow rate of nitrogen was controlled to be 15 L/min. The newborn rats were rapidly placed into the box after the concentration of oxygen was reduced to zero, and nitrogen was continuously passed into the box, and then opened the box channel to take out the newborn rats 10 minutes later.

B. (2) Place the neonate in a 100% oxygen environment and keep it there for 10 minutes.

C. (3) Immediately place in the refrigerator at 4 ℃ for 10 minutes. The newborn rats were treated 3 times a day and returned to the nursery box or the mother's cage for feeding for 3 consecutive days.

(C) LPS gavage: A

. LPS was diluted with 10 mg/kg in 0.1 mL of sterilized water and gavaged once a day for 3 consecutive days.

B. All experimental animals were fasted for 24 hours on the 4th day and then killed by decapitation. The presence of intestinal necrosis was regarded as a qualified animal model.

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