Wilmer J L, Erexson G L, Kligerman A D
Mutat Res. 1983 May;109(2):231-48. doi: 10.1016/0027-5107(83)90049-0.
One important variable in complex culture systems such as whole blood is the interaction of the cell types present. To investigate the effects of erythrocytes (RBCs) and monocytes on the sister-chromatid exchange (SCE) frequency, Ficoll-Hypaque-separated Fischer-344 rat leukocytes were added to 1.9 ml of culture medium containing either 4 micrograms phytohemagglutinin or 4-8 micrograms concanavalin A/ml. Bromodeoxyuridine (BrdU;2 microM) was added at 24 h, and the cultures were harvested at 54 or 72 h. SCE frequencies in the mononuclear leukocyte cultures were consistently about 1.5- to 2-fold higher than in the whole-blood cultures. The titration of rat or human RBCs (0.05-2.5 X 10(9)) into purified rat leukocyte cultures reduced the SCE frequency to that of whole-blood cultures. Monocyte depletion decreased the elevated SCE frequency by approximately 50%. Scintillation counting of [14C]BrdU uptake in isolated RBCs revealed that less than 8% of the total amount of BrdU was sequestered. Also, BrdU induced a concentration-dependent increase in SCE in purified leukocytes, but the absolute increase was no greater than in whole-blood lymphocytes. Thus, BrdU had a minor role in the elevated SCE frequency in purified lymphocytes. Neither anti-oxidant enzymes such as catalase and superoxide dismutase nor the hydroxyl radical scavenger, dimethyl sulfoxide, decreased the SCE frequency. Although purified human lymphocytes had a small, but significant increase in SCE compared to whole blood, the magnitude of the dichotomous response between man and rat may represent a fundamental species difference.
在诸如全血这样的复杂培养系统中，一个重要变量是所存在细胞类型之间的相互作用。为了研究红细胞（RBC）和单核细胞对姐妹染色单体交换（SCE）频率的影响，将经Ficoll - Hypaque分离的Fischer - 344大鼠白细胞添加到1.9毫升含有4微克植物血凝素或4 - 8微克刀豆球蛋白A/毫升的培养基中。在24小时时添加溴脱氧尿苷（BrdU；2微摩尔），并在54或72小时收获培养物。单核白细胞培养物中的SCE频率始终比全血培养物中的高约1.5至2倍。将大鼠或人红细胞（0.05 - 2.5×10⁹）滴定到纯化的大鼠白细胞培养物中，可将SCE频率降低至全血培养物的水平。单核细胞耗竭使升高的SCE频率降低了约50%。对分离的红细胞中[¹⁴C]BrdU摄取的闪烁计数显示，所隔离的BrdU总量不到8%。此外，BrdU在纯化的白细胞中诱导了SCE的浓度依赖性增加，但绝对增加幅度不大于全血淋巴细胞中的增加幅度。因此，BrdU在纯化淋巴细胞中SCE频率升高方面作用较小。过氧化氢酶和超氧化物歧化酶等抗氧化酶以及羟基自由基清除剂二甲基亚砜均未降低SCE频率。尽管纯化的人淋巴细胞与全血相比SCE有小幅但显著的增加，但人与大鼠之间二分反应的幅度可能代表了一种基本的物种差异。
