Morris S M, Domon O E, McGarrity L J, Aidoo A, Kodell R L, Casciano D A
Department of Health and Human Services, Food and Drug Administration, Jefferson, Arkansas.
Cell Biol Toxicol. 1993 Jan-Mar;9(1):77-83. doi: 10.1007/BF00755141.
Current studies in our laboratory are designed to determine the frequency of genotoxic responses induced in lymphocytes isolated from Fischer 344 rats. To evaluate the effect of a model compound, N-ethyl-N-nitrosourea (ENU), on the cell-cycle distribution of spleen lymphocytes, 8-week old, female Fischer 344 rats were injected i.p. with ENU and sacrificed 1, 2, 4, and 6 weeks after exposure. Four replicate cultures per dose per exposure period were established and cells were cultured for 66 hr. Colcemid, an agent which blocks cells in mitosis and induces an accumulation of cells in the G2 + M peak, was added to two of the four cultures as a positive control. After a 3 hr incubation, the cells were harvested, the nuclei stained with propidium iodide, and the DNA content of the individual nuclei was quantified by flow cytometry. As expected, exposure to Colcemid resulted in an accumulation of cells in the G2 + M phase of the cell cycle, which was accompanied by a decrease in the G0 + G1 population. The increase in the G2 + M population was significant (p < 0.05) in cultures of lymphocytes assayed at 4 and 6 weeks after exposure. The effect of increasing ENU concentration was an increase in the percentage of S-phase cells (p = 0.05) and a decrease (p < 0.02) in the percentage of G0 + G1 cells. This finding was observed only in those lymphocytes isolated 1 week after exposure.(ABSTRACT TRUNCATED AT 250 WORDS)
我们实验室目前的研究旨在确定从Fischer 344大鼠分离的淋巴细胞中诱导的基因毒性反应的频率。为了评估模型化合物N-乙基-N-亚硝基脲（ENU）对脾淋巴细胞细胞周期分布的影响，对8周龄的雌性Fischer 344大鼠腹腔注射ENU，并在暴露后1、2、4和6周处死。每个暴露期每个剂量建立四个重复培养物，细胞培养66小时。秋水仙酰胺是一种可使细胞阻滞在有丝分裂期并诱导细胞在G2 + M峰积累的试剂，在四个培养物中的两个中加入作为阳性对照。孵育3小时后，收获细胞，用碘化丙啶对细胞核进行染色，并通过流式细胞术对单个细胞核的DNA含量进行定量。正如预期的那样，暴露于秋水仙酰胺导致细胞在细胞周期的G2 + M期积累，同时伴随着G0 + G1群体的减少。在暴露后4周和6周测定的淋巴细胞培养物中，G2 + M群体的增加是显著的（p < 0.05）。增加ENU浓度的影响是S期细胞百分比增加（p = 0.05），G0 + G1细胞百分比减少（p < 0.02）。仅在暴露后1周分离的那些淋巴细胞中观察到这一发现。（摘要截断于250字）
