肠三叶因子对新生鼠坏死性小肠结肠炎模型ERK表达的影响

Effects of Intestional Trefoil Factor on the Expression of Extracellular Signal-regulated Kinase Signal in Neonatal Rat Model of Necrotizing Enterocolitis

目的:研究肠三叶因子(intestinaltrefoilfactor,ITF)对坏死性小肠结肠炎(necrotizingenterocolitis,NEC)新生大鼠的肠粘膜组织中细胞外信号调节激酶(extracellularsignalregulatedkinase,ERK)表达的影响,探讨ITF对NEC保护作用的信号途径;及ERK新生鼠肠组织中的活化及胞内分布规律,探讨其在NEC发病机制中的作用。方法:建立NEC模型,第4d处死,取肠组织待检。新生鼠40只随机分为5组,每组8只,A组为NEC模型后予以腹腔注射ITF0.5mg;B组为NEC模型后予以皮下注射ITF0.2mg;C、D组为NEC模型后分别予以腹腔和皮下注射生理盐水别为0.5ml和0.2ml;E组为正常对照组。取近回盲部1～2cm肠道组织固定包埋、切片、HE染色做病理学检查及免疫组化观察ERK的表达。结果:A、B组组织匀浆中ERK的面密度值各为87.68±19.24、82.65±21.35,较C、D组(30.23±7.79、30.74±8.19)明显升高(P<0.01),C、D组与E组(5.41±1.46)比较也有升高(P<0.05);并且随着ERK的激活伴随着明显的核转位。A、B组间及C、D组间ERK含量无显著差异(P>0.05);病理切片显示C、D组HE染色切片见肠壁损伤轻重不一,可见全肠粘膜绒毛坏死,病理评分的中位积分为3分;A、B组肠上皮细胞少量脱落,顶端绒毛坏死,病理评分的中位积分为1分。

Objective: To study effects of the intestinal trefoil factor (ITF) on extracellular signal-regulated kinase (ERK) density in neonatal rat necrotizing enterocolitis (NEC) models, to discuss whether ITF has protective function in NEC, and to investigate the intracellular distribution and the activation of ERK in neonatal rat intestinal tissues and the role in the mechanism of NEC. Methods: Forty neonatal rats are divided randomly into five groups according to different treatments as A: NEC+ITF 0.5ml, B: NEC+ ITF 0.2 ml, C: NEC+NS 0.5 ml, D: NEC+NS 0.2 ml and E: controls. NEC models of neonatal rats were established. On the 4th day, all subjects were put to death. Intestinal tissue located at the boundary of ileum and cecum was obtained to observe histological changes and the ERK level. Results: The density of ERK increased significantly in group A(87.68±19.24) and B(82.65±21.35) than those in group C(30.23±7.79) and D(30.74±8.19)(P<0.01), and increased in group C and D than those in group E (5.41±1.46)(P<0.05). Activation of ERK with evident nuclear translocation was found in hypoxia-induced in neonatal rat NEC model. And more, ERK contents between group A and B, group C and D were not dramatically different. The pathological lesions indicated that intestinal tissue necrosis was severe in group C and D, which were graded 3 points, but obviously lessened in group A and B, which was graded 1 point, with ITF interfering. Conclusion: Intestinal inflammation was ameliorated after ITF was injected hypodermically or intraperitoneally. ITF may provide a brand-new way for the therapy of NEC in neonatal rats. ERK signal pathways might play important roles in the mechanism and signal transduction of NEC. ITF may protect the intestinal injury of neonatal wistar rat NEC model by activation of ERK signal transduction pathway.