Rodriguez P, Heyman M, Candalh C, Blaton M A, Bouchaud C
Laboratoire de cytologie, Université Paris VI, CNRS URA 1488, France.
Cytokine. 1995 Jul;7(5):441-8. doi: 10.1006/cyto.1995.0060.
TNF-alpha is a widely distributed proinflammatory cytokine, involved in many disease states. Although it has widely distributed effects, a precise mechanism of action has never been described, in particular at the epithelial level. Morpho-functional changes of the intestinal epithelial monolayer HT29 cl.19A exposed to TNF-alpha were therefore assessed, using electron microscopy (including freeze-fracture replica analysis), as well as measurement of mannitol, Na+ and horseradish peroxidase fluxes across intestinal HT29 cl.19A cell monolayers using Ussing chambers. TNF-alpha receptors were induced on HT29 cl.19A cells by a small non-toxic dose of IFN-gamma (5 U/ml). After 4 h of the combined presence of TNF-alpha (10 ng/ml) and IFN-gamma (5 U/ml), the tight junction structure was altered as shown by a significant decrease in the average strand number measured in the apico-basal direction (5.50 +/- 2.70 vs 3.73 +/- 1.39 in control and treated cells respectively, P < 0.0001) and by a significant decrease in junctional depth (0.27 +/- 0.14 and 0.17 +/- 0.10 microns in control and treated cells respectively, P < 0.0001). These results are in agreement with a decrease in number of 'kiss' sites between contiguous membranes of TNF-alpha treated cells observed in ultrathin sections.(ABSTRACT TRUNCATED AT 250 WORDS)
肿瘤坏死因子-α（TNF-α）是一种广泛分布的促炎细胞因子，参与多种疾病状态。尽管它具有广泛的作用，但从未描述过其确切的作用机制，尤其是在上皮水平。因此，使用电子显微镜（包括冷冻断裂复型分析）以及使用尤斯灌流小室测量甘露醇、钠离子和辣根过氧化物酶跨肠道HT29 cl.19A细胞单层的通量，评估了暴露于TNF-α的肠道上皮单层HT29 cl.19A的形态功能变化。通过小剂量无毒的干扰素-γ（5 U/ml）在HT29 cl.19A细胞上诱导出TNF-α受体。在TNF-α（10 ng/ml）和干扰素-γ（5 U/ml）共同存在4小时后，紧密连接结构发生改变，这表现为在顶-基方向测量的平均链数显著减少（对照细胞和处理细胞分别为5.50±2.70和3.73±1.39，P<0.0001）以及连接深度显著降低（对照细胞和处理细胞分别为0.27±0.14和0.17±0.10微米，P<0.0001）。这些结果与在超薄切片中观察到的TNF-α处理细胞相邻膜之间“吻接”位点数量减少一致。（摘要截短于250字）
