Hagemann G, Kreczik A, Treichel M
Bereich Experimentelle Radiologie, Medizinischen Hochschule Hannover.
Strahlenther Onkol. 1996 Sep;172(9):507-11.
Following irradiation of the progenitor cells the clone growth of CHO cells decreases as a result of cell losses. Lethally acting expressions of micronuclei are produced by heritable lethal mutations. The dependency of the frequency of micronucleated binucleated clone cells and of the median clone sizes difference on the radiation dose was measured and compared to non-irradiated controls.
Using the cytokinesis-block-micronucleus-method binucleated cells with micronuclei were counted as ration of all binucleated cells within a clone size distribution. This ratio (shortened: micronucleus yield) was determined for all clone size distributions, which had been exposed to different irradiation doses and incubation times. The micronucleus yields were compared to the corresponding median clone sizes differences.
The micronucleus yield is linearly dependent on the dose and is independent of the incubation time. The same holds true for the division related median clone sizes difference, which as a result is also linearly dependent on the micronucleus yield.
Due to the inevitably errors of the cell count of micronucleated binucleated cells, an automatic measurement of the median clone sizes differences is the preferred method for evaluation of cellular radiation sensitivity for heritable lethal mutations. This value should always be determined in addition, if clone survival fractions are used as predictive test because it allows for an estimation of the remission probability of surviving cells.
祖细胞经照射后，由于细胞损失，CHO细胞的克隆生长会减少。微核的致死性作用表达是由可遗传的致死突变产生的。测量了双核克隆细胞中微核频率和克隆大小中位数差异对辐射剂量的依赖性，并与未照射的对照进行比较。
使用胞质分裂阻滞微核法，将有微核的双核细胞计为克隆大小分布内所有双核细胞的比例。对所有暴露于不同辐射剂量和孵育时间的克隆大小分布，测定该比例（简称为：微核产率）。将微核产率与相应的克隆大小中位数差异进行比较。
微核产率与剂量呈线性相关，且与孵育时间无关。与分裂相关的克隆大小中位数差异也是如此，因此它也与微核产率呈线性相关。
由于双核微核细胞计数不可避免地存在误差，自动测量克隆大小中位数差异是评估可遗传致死突变细胞辐射敏感性的首选方法。此外，如果将克隆存活分数用作预测性测试，应始终确定该值，因为它可以估计存活细胞的缓解概率。
