Nieto M A, González A, Gambón F, Díaz-Espada F, López-Rivas A
Instituto de Investigaciones Biomédicas del CSIC, Facultad de Medicina UAM, Madrid, Spain.
Clin Exp Immunol. 1992 May;88(2):341-4. doi: 10.1111/j.1365-2249.1992.tb03084.x.
Treatment of unfractionated human thymocytes in culture with the synthetic glucocorticoid dexamethasone induced cell death, as measured by trypan blue exclusion, after several hours of incubation. In purified subsets of human cortical and medullary thymocytes dexamethasone caused cell lysis with similar kinetics in both populations; 50% of thymocytes were killed after 20-24 h of incubation with the steroid. The mechanism of dexamethasone-induced cell death seems to correspond to apoptosis since degradation of DNA into oligonucleosome-sized fragments could be observed in the cultures treated with the steroid. A certain degree of DNA fragmentation and cell death could also be observed in control cultures of thymocytes. In contrast, peripheral T lymphocytes were resistant to the cytolytic effect of glucocorticoid hormone. The killing of human thymocytes by dexamethasone was inhibited by cycloheximide, suggesting that this cell death program requires a fully operating protein synthesis machinery and perhaps the induction of new proteins.
用合成糖皮质激素地塞米松处理培养中的未分级人胸腺细胞，经台盼蓝排斥法测定，孵育数小时后会诱导细胞死亡。在纯化的人皮质和髓质胸腺细胞亚群中，地塞米松在两个群体中引起细胞裂解，动力学相似；与类固醇孵育20 - 24小时后，50%的胸腺细胞被杀死。地塞米松诱导细胞死亡的机制似乎与凋亡相对应，因为在用类固醇处理的培养物中可以观察到DNA降解为寡核小体大小的片段。在胸腺细胞的对照培养物中也可观察到一定程度的DNA片段化和细胞死亡。相比之下，外周T淋巴细胞对糖皮质激素的细胞溶解作用具有抗性。环己酰亚胺抑制地塞米松对人胸腺细胞的杀伤作用，表明这种细胞死亡程序需要完全运行的蛋白质合成机制，可能还需要诱导新的蛋白质。
