Altered distribution of tight junction proteins after intestinal ischaemia/reperfusion injury in rats.
Altered distribution of tight junction proteins after intestinal ischaemia/reperfusion injury in rats.
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DOI：
10.1111/j.1582-4934.2009.00975.x
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发表时间：
2009-09
影响因子：
5.3
通讯作者：
Li J
中科院分区：
文献类型：
--
作者：
Li Q;Zhang Q;Wang C;Liu X;Qu L;Gu L;Li N;Li J
紧密连接(TJ)的中断在体外和最近的体内感染中都得到了证实。然而，TJ在缺血再灌注(I/R)损伤过程中变化的分子基础尚不清楚。在本研究中，我们在动物模型上建立了I/R引起的肠损伤模型。原位末端标记法和碘化丙啶摄取法显示，I/R损伤可诱导大鼠结肠细胞发生凋亡和坏死，其中再灌流5h时细胞凋亡率和坏死率最高。免疫荧光显微镜显示Claudins 1、3和5在结肠表面上皮细胞中有较强的表达，但I/R后这3种蛋白的标记在细胞内呈弥漫性分布，不再集中在细胞的侧缘。Occludin、ZO-1、claudin-1和claudin-3由TX-100不溶组分完全置换为TX-100可溶性组分，claudin-5部分置换。I/R后脂质筏标志物小窝蛋白-1的分布也发生了改变，分子示踪法显示TJs的损伤表现为Claudins 1、3和5的重新定位和肠通透性的增加。I/R损伤改变了TJ蛋白在体内的分布，这与功能性TJ缺陷有关。
Tight junction (TJ) disruptions have been demonstrated both in vitro and more recently in vivo in infection. However, the molecular basis for changes of TJ during ischaemia-reperfusion (I/R) injury is poorly understood. In the present study, intestinal damage was induced by I/R in an animal model. As assessed by TUNEL and propidium iodide uptake, we showed that I/R injury induced apoptosis as well as necrosis in rat colon, and the frequency of apoptotic and necrotic cells reached the maximum at 5 hrs of reperfusion. Immunofluorescence microscopy revealed that claudins 1, 3 and 5 are strongly expressed in the surface epithelial cells of the colon; however, labelling of all three proteins was present diffusely within cells and no longer focused at the lateral cell boundaries after I/R. Using Western blot analysis, we found that distribution of TJ proteins in membrane microdomains of TJ was markedly affected in I/R injury rats. Occludin, ZO-1, claudin-1 and claudin-3 were completely displaced from TX-100 insoluble fractions to TX-100 soluble fractions, and claudin-5 was partly displaced. The distribution of lipid raft marker protein caveolin-1 was also changed after I/R. I/R injury results in the disruption of TJs, which characterized by relocalization of the claudins 1, 3 and 5 and an increase in intestinal permeability using molecular tracer measurement. I/R injury altered distribution of TJ proteins in vivo that was associated with functional TJ deficiencies.