Intestinal epithelial apoptosis initiates gross bowel necrosis in an experimental rat model of neonatal necrotizing enterocolitis
Intestinal epithelial apoptosis initiates gross bowel necrosis in an experimental rat model of neonatal necrotizing enterocolitis
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DOI：
10.1203/01.pdr.0000113463.70435.74
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发表时间：
2004-04-01
影响因子：
3.6
通讯作者：
Caplan, MS
中科院分区：
文献类型：
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作者：
Jilling, T;Lu, J;Caplan, MS
坏死性小肠结肠炎（NEC）的组织病理学特征是在疾病的初始阶段粘膜层的破坏和在疾病的晚期阶段肠壁的透壁坏死。为了检验增强的上皮细胞凋亡是引起大体组织学变化的初始事件的假设，我们分析了NEC动物模型中的上皮细胞凋亡和组织形态，并评估了半胱天冬酶抑制对该模型中实验性NEC发生率的影响。通过末端脱氧核苷酸转移酶介导的dUTP-FITC缺口末端标记（TUNEL）染色法在肠切片中分析细胞凋亡，并通过测量来自配方奶粉喂养和冷/窒息应激（FFCAS）的新生大鼠和来自母亲喂养（MF）对照的肠裂解物的半胱天冬酶3活性来分析细胞凋亡。形态学评价基于肠切片的苏木精和伊红染色。FFCAS导致与NEC一致的组织学变化，MF动物中不存在这种变化。与MF相比，FFCAS还与小肠上皮细胞核DNA片段化率显著增加相关。组织caspase 3活性升高证实了DNA片段化增加的样品中存在细胞凋亡。相应组织切片中形态学损伤和凋亡的一致性分析表明，在该模型中，凋亡先于大体形态学变化。此外，补充具有8-叔丁氧羰基（OMe）-氟甲基酮（一种泛半胱天冬酶抑制剂）的配方显著降低了细胞凋亡和实验NEC的发生率。这些发现表明，在新生大鼠中，FFCAS诱导上皮细胞凋亡，其作为随后的大体组织坏死的潜在原因。
The histopathology of necrotizing enterocolitis (NEC) is characterized by destruction of the mucosal layer in initial stages and by transmural necrosis of the intestinal wall in advanced stages of the disease. To test the hypothesis that enhanced epithelial apoptosis is an initial event underlying the gross histologic changes, we analyzed epithelial apoptosis and tissue morphology in an animal model of NEC and evaluated the effect of caspase inhibition on the incidence of experimental NEC in this model. Apoptosis was analyzed with terminal deoxynucleotidyltransferase-mediated dUTP-FITC nick end labeling (TUNEL) staining in intestinal sections and by measuring caspase 3 activity from intestinal lysates of neonatal rats subjected to formula feeding and cold/asphyxia stress (FFCAS) and from mother-fed (MF) controls. Morphologic evaluation was based on hematoxylin and eosin staining of intestinal sections. FFCAS resulted in histologic changes consistent with NEC, which were absent from MF animals. FFCAS was also associated with a significantly increased rate of nuclear DNA fragmentation in the small intestinal epithelium compared with MF. Elevated tissue caspase 3 activity confirmed the presence of apoptosis in samples with increased DNA fragmentation. Analysis of the coincidence of morphologic damage and apoptosis in corresponding tissue sections indicated that apoptosis precedes gross morphologic changes in this model. Furthermore, supplementation of formula with 8 boc-aspartyl(OMe)-fluoromethylketone, a pan-caspase inhibitor, significantly reduced the incidences of apoptosis and experimental NEC. These findings indicate that in neonatal rats FFCAS induces epithelial apoptosis that serves as an underlying cause for subsequent gross tissue necrosis.