Nilsson Harriet, Dragomir Anca, Ahlander Anders, Johannesson Marie, Roomans Godfried M
Department of Medical Cell Biology, University of Uppsala, P.O. Box 571, 75123, Uppsala, Sweden.
Cell Tissue Res. 2007 Nov;330(2):257-69. doi: 10.1007/s00441-007-0482-7. Epub 2007 Sep 4.
Inhalation of hyperosmotic solutions (salt, mannitol) has been used in the treatment of patients with cystic fibrosis or asthma, but the mechanism behind the effect of hyperosmotic solutions is unclear. The relation between osmolarity and permeability changes was examined in an airway cell line by the addition of NaCl, NaBr, LiCl, mannitol, or xylitol (295-700 mOsm). Transepithelial resistance was measured as an indicator of the tightness of the cultures. Cell-cell contacts and morphology were investigated by immunofluorescence and by transmission electron microscopy, with lanthanum nitrate added to the luminal side of the epithelium to investigate tight junction permeability. The electrolyte solutions caused a significant decrease in transepithelial resistance from 450 mOsm upwards, when the hyperosmolar exposure was gradually increased from 295 to 700 mOsm; whereas the nonelectrolyte solutions caused a decrease in transepithelial resistance from 700 mOsm upwards. Old cultures reacted in a more rigid way compared to young cultures. Immuno-fluorescence pictures showed weaker staining for the proteins ZO-1, claudin-4, and plakoglobin in treated samples compared to the control. The ultrastructure revealed an increased number of open tight junctions as well as a disturbed morphology with increasing osmolarity, and electrolyte solutions opened a larger proportion of tight junctions than nonelectrolyte solutions. This study shows that hyperosmotic solutions cause the opening of tight junctions, which may increase the permeability of the paracellular pathway and result in increased transepithelial water transport.
吸入高渗溶液（盐、甘露醇）已用于治疗囊性纤维化或哮喘患者，但高渗溶液作用背后的机制尚不清楚。通过添加氯化钠、溴化钠、氯化锂、甘露醇或木糖醇（295 - 700毫渗量浓度），在一种气道细胞系中研究了渗透压与通透性变化之间的关系。测量跨上皮电阻作为培养物紧密性的指标。通过免疫荧光和透射电子显微镜研究细胞间接触和形态，向上皮腔侧添加硝酸镧以研究紧密连接的通透性。当高渗暴露从295毫渗量浓度逐渐增加到700毫渗量浓度时，电解质溶液从450毫渗量浓度起导致跨上皮电阻显著降低；而非电解质溶液从700毫渗量浓度起导致跨上皮电阻降低。与年轻培养物相比，老龄培养物的反应更僵硬。免疫荧光图片显示，与对照相比，处理样品中紧密连接蛋白1（ZO - 1）、闭合蛋白4和桥粒斑蛋白的染色较弱。超微结构显示，随着渗透压增加，开放紧密连接的数量增加，形态紊乱，并且电解质溶液比非电解质溶液打开的紧密连接比例更大。这项研究表明，高渗溶液会导致紧密连接开放，这可能会增加细胞旁途径的通透性，并导致跨上皮水转运增加。
