Ijiri K, Potten C S
Int J Radiat Biol Relat Stud Phys Chem Med. 1984 Nov;46(5):609-23. doi: 10.1080/09553008414551801.
Within 3-6 h of small doses of radiation (gamma-rays) the number of dead cells (apoptotic cells) in the crypts of the small intestine reaches peak values. These return to normal levels only after times later than 1 day. After higher doses elevated levels of cell death persist for longer times. The dead cells first occur most frequently at the lower positions of the crypt (median value for the distribution of apoptotic fragments is about cell position 6). At later times more dead cells are observed at higher positions. Two doses of radiation separated by various time intervals have been used to investigate when after irradiation the cell population susceptible to acute cell death is re-established. Dead cells were scored 3 or 6 h after the second dose. The yield of dead cells after two doses represents the sum of the dead cells produced by, and persisting from, the first dose and new apoptotic cells induced by the second dose. Since the temporal and dose-dependence aspects of the dead-cell yield after the first dose alone is known, the additional dead cells attributable to the second dose alone can be determined by subtraction. Within 1-2 days of small doses (0.5 Gy) the sensitive cells, recognized histologically as apoptotic cells, are re-established at the base of the crypt (around cell position 6). After higher doses (9.0 Gy) they are not re-established until about the fourth day after irradiation. Even in the enlarged regenerating crypts the sensitive cells are found at the same position at the crypt base. It has been estimated that the crypt contains five or six cells that are susceptible to low doses (0.5 Gy) (hypersensitive cells) and up to a total of only seven or eight susceptible cells that can be induced by any dose to enter the sequence of changes implicit in apoptosis. Between 4 and 10 days after an initial irradiation of 9.0 Gy the total number of susceptible cells increased from seven to eight to about 10 to 13 per crypt.
在小剂量辐射（γ射线）照射3至6小时内，小肠隐窝中的死亡细胞（凋亡细胞）数量达到峰值。这些细胞数量只有在1天以后才恢复到正常水平。更高剂量照射后，细胞死亡水平升高的持续时间更长。死亡细胞最初最常出现在隐窝的较低位置（凋亡碎片分布的中位数约为细胞位置6）。在稍后的时间里，在较高位置观察到更多的死亡细胞。使用间隔不同时间的两剂辐射来研究照射后何时重新建立易发生急性细胞死亡的细胞群体。在第二剂辐射后3或6小时对死亡细胞进行计数。两剂辐射后的死亡细胞产量代表第一剂产生并持续存在的死亡细胞与第二剂诱导的新凋亡细胞之和。由于仅第一剂辐射后死亡细胞产量的时间和剂量依赖性方面是已知的，因此可以通过减法确定仅归因于第二剂辐射的额外死亡细胞。在小剂量（0.5 Gy）照射后的1至2天内，在组织学上被识别为凋亡细胞的敏感细胞在隐窝底部（细胞位置6左右）重新建立。更高剂量（9.0 Gy）照射后，它们直到照射后约第四天才重新建立。即使在扩大的再生隐窝中，敏感细胞也位于隐窝底部的相同位置。据估计，隐窝中含有五六个对低剂量（0.5 Gy）敏感的细胞（超敏感细胞），并且任何剂量诱导进入凋亡隐含变化序列最多总共只有七八个敏感细胞。在9.0 Gy初始照射后的4至10天内，每个隐窝中敏感细胞的总数从七八个增加到约10至13个。
