Takeshita T, Ariizumi-Shibusawa C, Shimizu K, Hoshino H, Yamagata Z, Iijima S, Asaka A, Higurashi M
Department of Health Sciences, Yamanashi Medical College, Japan.
Mutat Res. 1992 Jan;275(1):21-9. doi: 10.1016/0921-8734(92)90005-a.
To evaluate the effects of aging on cytogenetic characteristics of lymphocytes from Down syndrome (DS), cell-cycle kinetics after PHA stimulation and chromosome-type aberration frequencies after X-ray exposure were investigated in vitro in the lymphocytes derived from 4 (or 3 for X-ray treatment) age groups of DS patients and age-matched controls. The results clearly showed higher mitotic and proliferation index levels in younger groups compared to older groups at the various culture intervals, whether the lymphocytes were from the DS patients or controls. The age-related changes of the proliferation index were mainly attributed to a delayed response to PHA as age increased. The changes of PHA responses seemed to be particularly marked during adolescence. Nonetheless, no significant differences were observed between the DS patients and age-matched controls for each age group. In all age groups, frequencies of both chromosome-type exchanges and deletions were elevated in the DS patients by about 1.3 times in comparison with the controls. The magnitude of radiosensitivity, however, seemed to decrease slightly in the 40-49-year group. To our knowledge, the present study is the first report in the literature to deal with the effect of aging on the greater radiosensitivity of DS lymphocytes.
为评估衰老对唐氏综合征（DS）患者淋巴细胞细胞遗传学特征的影响，我们对来自4个（X射线处理组为3个）年龄组的DS患者及年龄匹配对照的淋巴细胞进行体外研究，观察了PHA刺激后的细胞周期动力学以及X射线照射后的染色体型畸变频率。结果清楚显示，在各个培养时间段，无论淋巴细胞来自DS患者还是对照，较年轻组的有丝分裂和增殖指数水平均高于较年长组。增殖指数的年龄相关变化主要归因于随着年龄增长对PHA的反应延迟。PHA反应的变化在青春期似乎尤为明显。然而，每个年龄组的DS患者与年龄匹配对照之间未观察到显著差异。在所有年龄组中，DS患者的染色体型交换和缺失频率均比对照升高约1.3倍。不过，40 - 49岁组的放射敏感性似乎略有下降。据我们所知，本研究是文献中首篇探讨衰老对DS淋巴细胞更高放射敏感性影响的报告。
