Waters C M, Glucksberg M R, Depaola N, Chang J, Grotberg J B
Department of Anesthesia, Northwestern University, Chicago, Illinois 60611, USA.
J Appl Physiol (1985). 1996 Jul;81(1):448-58. doi: 10.1152/jappl.1996.81.1.448.
The sliding motion of the lung against the chest wall creates a shear stress in the pleural space, which can be as high as 60 dyn/cm2, depending on the respiration rate. Such shear stresses may affect the mesothelial cells that line the pleural space on the lung (visceral pleura) and chest wall (parietal pleura). When exposed to shear stress (17 dyn/cm2) in a parallel-plate flow chamber for 22 h, rat visceral pleura mesothelial cells were not altered morphologically and did not align in the direction of flow, in contrast to the shape changes observed for bovine aortic endothelial cells. By using mesothelial cells cultured on porous microcarrier beads, we measured the permeability of the cells at different flows in a cell-column chromatography assay. The permeabilities to sodium fluorescein and cyanocobalamin increased from 8.2 +/- 1.0 and 7.8 +/- 0.7 x 10(-5) cm/s to 22.5 +/- 1.2 and 21.8 +/- 3.0 x 10(-5) cm/s, respectively, when the flow was increased from 0.9 to 3.5 ml/min (corresponding to average shear stresses of 4.7-18.4 dyn/cm2). The permeabilities returned to baseline values when the flow was reduced. Cytochalasin D stimulated an increase in permeability that was not augmented by a subsequent increase in shear stress. These results suggest that the barrier function of mesothelial cells is responsive to changes in fluid shear stress.
肺与胸壁之间的滑动运动会在胸膜腔中产生剪切应力，其大小取决于呼吸频率，最高可达60达因/平方厘米。这种剪切应力可能会影响覆盖在肺（脏层胸膜）和胸壁（壁层胸膜）胸膜腔表面的间皮细胞。与牛主动脉内皮细胞观察到的形状变化不同，大鼠脏层胸膜间皮细胞在平行板流动腔中暴露于剪切应力（17达因/平方厘米）22小时后，形态未发生改变，且未沿流动方向排列。通过使用在多孔微载体珠上培养的间皮细胞，我们在细胞柱色谱分析中测量了不同流速下细胞的通透性。当流速从0.9毫升/分钟增加到3.5毫升/分钟（相当于平均剪切应力为4.7 - 18.4达因/平方厘米）时，对荧光素钠和钴胺素的通透性分别从8.2±1.0和7.8±0.7×10⁻⁵厘米/秒增加到22.5±1.2和21.8±3.0×10⁻⁵厘米/秒。当流速降低时，通透性恢复到基线值。细胞松弛素D刺激通透性增加，随后剪切应力增加并未使其进一步增强。这些结果表明间皮细胞的屏障功能对流体剪切应力的变化有反应。
