Intestinal barrier disruption as a cause of mortality in combined radiation and burn injury.
Intestinal barrier disruption as a cause of mortality in combined radiation and burn injury.
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DOI：
10.1097/shk.0b013e3182a2c5b5
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发表时间：
2013-10
期刊：
影响因子：
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通讯作者：
Kovacs EJ
中科院分区：
文献类型：
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作者：
Carter SR;Zahs A;Palmer JL;Wang L;Ramirez L;Gamelli RL;Kovacs EJ
核灾难与辐射损伤（CRI）和创伤或烧伤的联合损伤相比，导致更高的死亡率。早期死亡是由胃肠道（GI）渗漏的后遗症，如细菌移位和休克引起的。我们开发了一种小鼠模型来表征CRI后GI损伤并确定屏障破坏的程度。动物接受单独的辐射（5.5戈伊）或15%总体表面积（TBSA）烧伤，并在24、48和72 h处以安乐死。将肠系膜淋巴结匀浆铺在胰蛋白酶大豆琼脂上以评估细菌移位。紧密连接蛋白，occludin，其特征在于通过Western印迹和免疫荧光。肠组织学进行了评估，并使用组蛋白相关的DNA片段化酶联免疫吸附试验和蛋白质印迹法的caspase-3和caspase-8的细胞凋亡进行定量。在72小时，观察到CRI后细菌生长增加100倍。辐射暴露减少了Occludin共定位，CRI在24和48小时差异最大。组织学检查显示单纯放疗组和CRI组24、48 h细胞凋亡率均明显升高（P< 0.05）。在48 h时观察到CRI中凋亡活性的进一步证据，相对于所有组，酶联免疫吸附测定检测增加3倍，并且相对于单独辐射和假手术，caspase-8活性增加（P< 0.05）。持续的上皮细胞凋亡和紧密连接的破坏可能有助于CRI后的肠漏。随后细菌移位至肠系膜淋巴结可能导致败血症和死亡，并可作为缓解剂的靶点，以改善CRI的生存率。
Nuclear disaster associated with combined radiation injury (CRI) and trauma or burns results in higher mortality than component injuries. Early death is caused by sequelae of gastrointestinal (GI) leakiness such as bacterial translocation and shock. We developed a murine model to characterize GI injury after CRI and determine the extent of barrier disruption. Animals received radiation (5.5 Gy) alone or with 15% total body surface area (TBSA) scald burn and were euthanized at 24, 48, and 72 h. Mesenteric lymph node homogenate was plated on tryptic soy agar to assess for bacterial translocation. Tight junction protein, occludin, was characterized by Western blot and immunofluorescence. Intestinal histology was evaluated, and apoptosis was quantified using histone-associated DNA fragmentation enzyme-linked immunosorbent assay and Western blot for caspase-3 and caspase-8. At 72 h, a 100-fold increase in bacterial growth after CRI was observed. Occludin colocalization was reduced by radiation exposure, with largest differences in CRI at 24 and 48 h. Histopathology exhibited increased apoptosis in radiation alone and CRI animals at 24 and 48 h (P< 0.05). Further evidence of apoptotic activity in CRI was seen at 48 h, with 3-fold increases in enzyme-linked immunosorbent assay detection relative to all groups and caspase-8 activity relative to radiation alone and sham (P< 0.05). Prolonged epithelial apoptosis and disruption of tight junctions likely contribute to gut leakiness after CRI. Subsequent bacterial translocation to mesenteric lymph node potentially leads to sepsis and death and could serve as a target for mitigating agents to improve survival from CRI.