Cai L, Liu S Z
Department of Radiation Biology, Norman Bethune University of Medical Sciences, Changchun, China.
Int J Radiat Biol. 1990 Jul;58(1):187-94. doi: 10.1080/09553009014551541.
The cytogenetic adaptive response induced by low-level radiation was studied using human and rabbit lymphocytes in vitro and bone marrow cells and germ cells in vivo. The inductive dose of X-rays was 10 mGy for the in vitro studies at a dose rate of 10 mGy/min, and 2, 10, 50, 75 and 100 mGy for the in vivo studies at a dose rate of 50 mGy/min. The challenging dose was 1.5 Gy X-rays for the in vitro experiments and 0.65 or 0.75 Gy for the in vivo experiments at a dose rate of 0.44 Gy/min. The results reported here, in addition to those that have appeared in the literature, show the following characteristics documented for the first time: (1) 10 mGy could induce the adaptive response in human as well as rabbit lymphocytes irradiated not only in G1, S and G2 phases, but also in the Go state; (2) although the induced adaptive response could only last three cell cycles, it could be revived when the inductive dose was repeated after the third cell cycle; (3) the adaptive response could be induced by low-dose X-rays in somatic cells, both in vitro (lymphocytes) and in vivo (bone marrow cells), and also in germ cells (spermatocytes); (4) the magnitude of the adaptive response induced by whole-body irradiation was found to be dose-dependent--the lower the inductive dose the more the reduction of the frequency of chromatid aberrations following the challenging dose.
利用人及兔淋巴细胞体外培养以及骨髓细胞和生殖细胞体内实验，研究了低水平辐射诱导的细胞遗传学适应性反应。体外研究中，X射线诱导剂量为10 mGy，剂量率为10 mGy/min；体内研究中，诱导剂量为2、10、50、75和100 mGy，剂量率为50 mGy/min。体外实验的激发剂量为1.5 Gy X射线，体内实验的激发剂量为0.65或0.75 Gy，剂量率为0.44 Gy/min。除文献中已报道的结果外，本文报道的结果首次显示出以下特征：（1）10 mGy不仅能诱导处于G1、S和G2期的人及兔淋巴细胞产生适应性反应，还能诱导处于Go期的淋巴细胞产生适应性反应；（2）虽然诱导的适应性反应仅能持续三个细胞周期，但在第三个细胞周期后重复诱导剂量时，该反应可以恢复；（3）低剂量X射线能在体细胞中诱导适应性反应，包括体外（淋巴细胞）和体内（骨髓细胞），也能在生殖细胞（精母细胞）中诱导适应性反应；（4）发现全身照射诱导的适应性反应程度与剂量相关——诱导剂量越低，激发剂量后染色单体畸变频率降低越多。
