Zani A, Cordischi L, Cananzi M, De Coppi P, Smith V V, Eaton S, Pierro A
Department of Paediatric Surgery, Institute of Child Health, London, UK.
Eur J Pediatr Surg. 2008 Dec;18(6):423-6. doi: 10.1055/s-2008-1038951. Epub 2008 Nov 14.
A neonatal rat model of necrotizing enterocolitis (NEC) is useful to investigate this devastating and obscure disease. The aim of this study was to assess a neonatal rat model of NEC to evaluate whether the histological appearance of the damaged intestine could be predicted by the clinical behaviour of the animals and the macroscopic appearance of the gut.
Neonatal rats were delivered at term and assigned either to a control group consisting of breastfeeding and no stress factors, or to a NEC group in which NEC was induced by gavage feeding + hypoxia + oral lipopolysaccharide (4 mg/kg/day once daily for the first 2 days of life). Clinical status was assessed on day 4 using a clinical sickness score (general appearance, response to touch, natural activity, body colour; 0 - 3 for each variable). Neonatal rats were sacrificed at 4 different time points: day 1, day 2, day 3, and day 4. At sacrifice, a macroscopic assessment of the gut was performed using a new scoring system based on: colour (0 - 2), consistency (0 - 2) and degree of dilatation (0 - 2). The resected gut was stained with haematoxylin/eosin, and evaluated microscopically by 2 independent blinded scorers, including a consultant histopathologist. The histology results were used to validate the macroscopic gut assessment. Results were compared by ANOVA and linear regression analysis. Ethics Committee and Home Office approvals were obtained.
In the control group NEC was not present either macroscopically or histologically. The clinical sickness score was higher in the NEC group (median = 4.5; range = 2 - 6) compared to controls (median = 0; range = 0 - 1; p < 0.0001). In the NEC group the macroscopic appearance (from day 2) and histological score (from day 1) increased significantly (p < 0.0001) and were strongly correlated (r (2) = 0.74, p < 0.0001).
The clinical behaviour and macroscopic appearance of the intestine are valid tools to assess gut damage in our neonatal rat model of NEC. This allows future studies that are not exclusively based on histology.
坏死性小肠结肠炎（NEC）的新生大鼠模型对于研究这种毁灭性且病因不明的疾病很有用。本研究的目的是评估一种NEC新生大鼠模型，以确定受损肠道的组织学表现是否可以通过动物的临床行为和肠道的宏观外观来预测。
足月分娩的新生大鼠被分为两组，一组为对照组，采用母乳喂养且无应激因素；另一组为NEC组，通过灌胃喂养+缺氧+口服脂多糖（出生后前两天每天一次，4mg/kg/天）诱导NEC。在第4天使用临床疾病评分（一般外观、对触摸的反应、自然活动、身体颜色；每个变量0-3分）评估临床状态。新生大鼠在4个不同时间点处死：第1天、第2天、第3天和第4天。处死时，使用基于颜色（0-2分）、质地（0-2分）和扩张程度（0-2分）的新评分系统对肠道进行宏观评估。切除的肠道用苏木精/伊红染色，并由2名独立的盲法评分者进行显微镜评估，其中包括一名顾问组织病理学家。组织学结果用于验证肠道宏观评估。结果通过方差分析和线性回归分析进行比较。获得了伦理委员会和内政部的批准。
对照组在宏观和组织学上均未出现NEC。与对照组（中位数=0；范围=0-1；p<0.0001）相比，NEC组的临床疾病评分更高（中位数=4.5；范围=2-6）。在NEC组中，宏观外观（从第2天开始）和组织学评分（从第1天开始）显著增加（p<0.0001），且相关性很强（r(2)=0.74，p<0.0001）。
在我们的NEC新生大鼠模型中，临床行为和肠道宏观外观是评估肠道损伤的有效工具。这使得未来的研究不必完全基于组织学。
