不同日龄新生SD大鼠坏死性小肠结肠炎模型建立

Establishment of Necrotizing Enterocolitis Model in SD Rats with Different Ages

目的建立并比较二种不同日龄新生SD大鼠坏死性小肠结肠炎(NEC)模型。方法出生2 h内及出生48 h SD大鼠各24只,随机分为人工喂养组(A、B组)、人工喂养+脂多糖(LPS)组(C、D组)和对照组(E、F组),即出生2 h的A、C、E组及48 h的B、D、F组。A、B、C、D组均予以缺氧+冷刺激每日2次;C、D组每日LPS灌胃1次;对照组仅母鼠喂养。实验84 h后空腹处死,取出回盲部近端肠管1 cm,HE染色后观察肠组织形态学,进行病理评分。结果实验组大鼠相继出现不同程度排黄绿色黏液稀便、腹胀、胃潴留、呕吐、嗜睡,活动度下降,并逐渐加重,体质量增长缓慢;对照组新生大鼠纳乳好,生长发育良好。A、B、C、D组组织学病理积分和NEC发生率均明显高于对照组。结论新生SD大鼠出生2 h内及出生48 h在人工灌胃喂养、低体温和缺氧条件下可诱导出符合NEC临床表现和组织学特征的大鼠模型,LPS灌胃可加重临床表现和组织学病理改变。

Objective To establish and compare two models of necrotizing enterocolitis( NEC in neonatal SD rats at different ages. Methods New born SD rats within postal 2 hours and 48 hours(each time point 24 rats) were randomly divided into three groups respectively according to body weight as the artificial feeding group( groups A, B), the artificial feeding + lipopolysaccharide(LPS)group(groups C, D), and control group(groups E, F), namely postal 2 hours(groups A, C, E) and postal 48 hours(group B, D, F). The rats in 4 groups A, B, C and D were treated with hypoxia plus cold stimulation twice a day, group C and D were also given LPS once a day by gavage, and the control group was fed only by female rats. The rats were executed 84 hours after the experiment time point with fasting. The proximal ileocecal ileum was removed about 1 cm for histomorphological observation. The intestinal histomorphology was observed and the intestinal histopathological score was made. Results The rats in group A, B, C and D had yellow-green mucus defecation, abdominal distension, slow weight growth, gastric retention, vomiting, lethargy, decreased activity and gradually aggravated. Neonatal rats in two control groups had better milk intake, good growth and development. The histological scores and the incidence of NEC in groups A, B, C, and D were significantly higher than those of control groups. Conclusion NEC-compliant models both can be induced in neonatal SD rats within postal 2 hours and 48 hours by artificial nasal feeding, low body temperature and hypoxia, LPS gavage can aggravate the clinical manifestations and histopathological changes.