肠型脂肪酸结合蛋白在新生大鼠坏死性小肠结肠炎肠道组织中的表达及意义

Intestinal fatty acid-binding protein expression in the intestinal tissue and clinical significance in neonatal rats with necrotizing enterocolitis

目的探讨新生大鼠坏死性小肠结肠炎(necrotizing enterocolitis,NEC)发病过程中肠型脂肪酸结合蛋白(intestinal fatty acid-binding protein,I-FABP)表达变化及意义.方法新生SD大鼠24只随机分为对照组、NEC模型1组、NEC模型2组、NEC模型3组,每组6只.新生大鼠生后48 h内与母鼠同笼,由母鼠喂养.48 h后NEC模型组通过人工喂养+缺氧+冷刺激+脂多糖灌胃(10 mg/kg)建立NEC模型,并分别在造模结束后1、2、3 d空腹处死;对照组不干预,在NEC模型组造模结束后3 d空腹处死.取各组大鼠回盲部肠管固定或冻存,采用苏木精-伊红染色观察小肠组织病理改变并评分;应用实时定量聚合酶链反应法检测大鼠肠道I-FABP mRNA转录水平,酶联免疫吸附法检测大鼠肠道I-FABP蛋白表达水平.结果 NEC模型1组、NEC模型2组、NEC模型3组造模结束后体重均明显低于对照组,差异有统计学意义(P<0.001);肠组织病理评分分别为2(2,3)分、3(2,3)分、4(3,4)分,与对照组相比明显增高,差异有统计学意义(P<0.05).NEC模型1组、NEC模型2组、NEC模型3组大鼠肠道I-FABP mRNA转录水平分别为2.69±0.27、2.12±0.09、3.18±0.22,蛋白表达水平分别为363.7±11.4、321.7±45.8、432.3±50.3,均显著高于对照组(1.00±0.02和134.2±24.0),差异有统计学意义(P<0.05).结论 I-FABP是肠道缺血性损伤的有效标志物,检测I-FABP可能有助于新生儿NEC的早期诊断.

Objective To study the expression of intestinal intestinal fatty acid-binding protein (I-FABP) and its clinical significance in an experimental model of necrotizing enterocolitis (NEC) in neonatal rats. Method Twenty-four neonatal Sprague-Dawley (SD) rats were randomly assigned into 4 groups at 48 h after birth (6 rats in each group): group A (control group), group B (NEC group-1), group C (NEC group-2), and group D (NEC group-3). The neonatal rats were fed by the mother rats in the same cage within 48 h after birth. After 48 h, the NEC group received artificial feeding, hypoxia, cold stimulation and lipopolysaccharide (LPS) gavage (10 mg/kg). NEC group-1, 2 and 3 were sacrificed on an empty stomach at 1, 2 and 3 d after the modeling. The control group was sacrificed on an empty stomach 3 d after the modeling without special treatment. Intestinal tissue were obtained from each rats. The histological changes of ileal tissues were studied using hematoxylin-eosin (HE) staining. The expressions of intestinal I-FABP were detected using RT-PCR and ELISA methods. Result Compared with the control group, body weight of rats in NEC group-1, 2 and 3 were lower, and pathology scores in these three groups were higher (P<0.05). The levels of intestinal I-FABP mRNA in NEC group-1, NEC group-2 and NEC group-3 were 2.69±0.27, 2.12±0.09, 3.18±0.22, respectively. The protein expression levels were 363.7±11.4, 321.7±45.8, 432.3±50.3, respectively. The mRNA and protein levels were all significantly higher than the control group (mRNA: 1.00±0.02, protein: 134.2±24.0, P<0.05). Conclusion I-FABP was a useful marker for ischemic injury to the intestine. These findings may contribute to a better diagnosis of NEC in newborns.