Rubin D B, Drab E A, Bauer K D
Department of Medicine, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois.
J Appl Physiol (1985). 1989 Oct;67(4):1585-90. doi: 10.1152/jappl.1989.67.4.1585.
Vascular endothelial cells (EC) are important clinical targets of radiation and other forms of free radical/oxidant stresses. In this study, we found that the extent of endothelial damage may be determined by the different cytotoxic responses of EC subpopulations. The following characteristics of EC subpopulations were examined: 1) cell volume; 2) cell cycle position; and 3) cytotoxic indexes for both acute cell survival and proliferative capacity after irradiation (137Cs, gamma, 0-10 Gy). EC cultured from bovine aortas were separated by centrifugal elutriation into subpopulations of different cell volumes. Through flow cytometry, we found that cell volume was related to the cell cycle phase distribution. The smallest EC were distributed in G1 phase and the larger cells were distributed in either early S, middle S, or late S + G2M phases. Cell cycle phase at the time of irradiation was not associated with acute cell loss. However, distribution in the cell cycle did relate to cell survival based on proliferative capacity (P less than 0.01). The order of increasing radioresistance was cells in G1 (D0 = 110 cGy), early S (135 cGy), middle S (145 cGy), and late S + G2M phases (180 cGy). These findings 1) suggest an age-related response to radiation in a nonmalignant differentiated cell type and 2) demonstrate EC subpopulations in culture.
血管内皮细胞（EC）是辐射及其他形式自由基/氧化应激的重要临床靶点。在本研究中，我们发现内皮损伤程度可能由EC亚群不同的细胞毒性反应决定。我们检测了EC亚群的以下特征：1）细胞体积；2）细胞周期位置；3）照射（¹³⁷Cs，γ，0 - 10 Gy）后急性细胞存活和增殖能力的细胞毒性指数。通过离心淘洗法将牛主动脉培养的EC分离成不同细胞体积的亚群。通过流式细胞术，我们发现细胞体积与细胞周期阶段分布相关。最小的EC分布在G1期，较大的细胞分布在早S期、中S期或晚S + G2M期。照射时的细胞周期阶段与急性细胞丢失无关。然而，基于增殖能力，细胞周期分布与细胞存活相关（P < 0.01）。放射抗性增加的顺序为G1期细胞（D0 = 110 cGy）、早S期（135 cGy）、中S期（145 cGy）和晚S + G2M期（180 cGy）。这些发现1）提示在非恶性分化细胞类型中存在与年龄相关的辐射反应，2）证明了培养中的EC亚群。
