Lundberg K
Department of Toxicology, Uppsala University, Sweden.
Biochem Biophys Res Commun. 1991 Jul 15;178(1):16-23. doi: 10.1016/0006-291x(91)91773-6.
The effects of in vivo exposure to dexamethasone (DEX) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on thymocyte proliferation and thymocyte number were compared. In the thymus of DEX-treated mice (1 mg/kg) both proliferation and cell number had decreased by 70% one day after exposure. This decrease was, however, transient, and values returned to normal within 2 weeks. By contrast, in TCDD exposed mice (50 micrograms/kg), a reduction in proliferation was not observed until day 2 after exposure, and the degree of reduction was only about 50%. By this point in time, cell number had only decreased by 20%. Proliferation increased again on day 3 after TCDD administration, whereas cell number continued to decrease and remained low throughout the observation period (8 days). DEX had a direct and immediate effect on cells in all thymocyte subpopulations whereas TCDD initially only affected the immature double negative (DN) and double positive (DP) populations.
比较了体内暴露于地塞米松（DEX）和2,3,7,8-四氯二苯并对二恶英（TCDD）对胸腺细胞增殖和胸腺细胞数量的影响。在接受DEX治疗的小鼠（1毫克/千克）胸腺中，暴露后一天增殖和细胞数量均下降了70%。然而，这种下降是短暂的，数值在2周内恢复正常。相比之下，在暴露于TCDD的小鼠（50微克/千克）中，直到暴露后第2天才观察到增殖减少，减少程度仅约为50%。此时，细胞数量仅减少了20%。在给予TCDD后第3天增殖再次增加，而细胞数量继续减少并在整个观察期（8天）内保持较低水平。DEX对所有胸腺细胞亚群中的细胞都有直接且即时的作用，而TCDD最初仅影响未成熟的双阴性（DN）和双阳性（DP）群体。
