Absher M, Makrides W, Shapiro P, Evans J N
Department of Molecular Physiology and Biophysics, University of Vermont College of Medicine, Burlington 05405.
Am J Physiol. 1994 Aug;267(2 Pt 1):L101-5. doi: 10.1152/ajplung.1994.267.2.L101.
Exposure of the lung to elevated oxygen leads to structural and cellular injury followed by extensive tissue remodeling. In vitro models utilizing isolated cells exposed to hyperoxic conditions or exogenously added oxidants may be injurious or stimulatory depending on the specific cell type and level and duration of exposure. In the present study, proliferation of cultured rat tracheal smooth muscle cells was inhibited by oxygen concentrations of 40 and 70% compared with a "normoxic" concentration of 21%. Exposure to 70% oxygen had a hypertrophic effect on the cells, as indicated by increased cellular protein content, whereas cells exposed to 21% oxygen did not show increased protein content. Exogenously added oxidant, H2O2, resulted in complete inhibition of growth of tracheal smooth muscle cells at concentrations > 3 microM. Much higher concentrations of H2O2 were required to inhibit proliferation of vascular smooth muscle cells and rat lung fibroblasts. The heightened sensitivity of airway smooth muscle cells to oxygen and oxidants may be an important factor in the early events following hyperoxia-induced lung injury.
肺部暴露于高氧环境会导致结构和细胞损伤，随后引发广泛的组织重塑。利用分离细胞暴露于高氧条件或外源性添加氧化剂的体外模型，根据特定细胞类型、暴露水平和持续时间的不同，可能具有损伤性或刺激性。在本研究中，与“常氧”浓度21%相比，40%和70%的氧浓度抑制了培养的大鼠气管平滑肌细胞的增殖。暴露于70%氧气对细胞有肥大作用，表现为细胞蛋白含量增加，而暴露于21%氧气的细胞蛋白含量未增加。外源性添加的氧化剂过氧化氢（H2O2）在浓度>3 microM时完全抑制气管平滑肌细胞的生长。抑制血管平滑肌细胞和大鼠肺成纤维细胞的增殖需要更高浓度的H2O2。气道平滑肌细胞对氧气和氧化剂的高敏感性可能是高氧诱导的肺损伤早期事件中的一个重要因素。
