van den Aardweg G J, de Ruiter-Bootsma A L, Kramer M F, Davids J A
Radiat Res. 1983 Jun;94(3):447-63.
The longitudinal outgrowth of spermatogenetic colonies arising from stem cells that survived neutron doses of 150, 300, and 350 rad was studied up to 30 weeks in histological sections of CBA mouse testes. Two methods were used: (1) the repopulation index (RI) as a measure of the length of total colonies per testis and (2) measurement of the individual length of all colonies in serially sectioned testes 4 and 15 weeks after 300 rad and 15 weeks after 350 rad. The mean initial growth of the colonies is linear up to 8, 15, and 20 weeks after 150, 300, and 350 rad, respectively. Although after these doses the mean initial colony growth rate did not differ significantly (about 27 microns/day), both methods showed that the colonies grow about 20% slower after 350 rad. Screening of individual colonies revealed a great variation in colony length per testis and a higher frequency of short colonies with higher neutron doses. Counting of colonies after 300 rad showed that all surviving stem cells had started to form a colony within 4 weeks after irradiation. The development of spermatogenetic cells to mature spermatozoa was studied after 100, 150, 300, and 350 rad in sections of repopulating tubules used for RI determination as well as in serial sections of individual colonies. Although after 300 and 350 rad spermatogenetic cell types beyond the stage of young spermatocytes reappeared 1 week late, we found no great disturbances in the regular reappearance of the successive spermatogenetic cell types after irradiation. However, from the study of individual colonies it appeared that colonies differ widely in their development even within one testis. Moreover, the frequency of less developed colonies was higher after 350 rad than after 300 rad. Our data suggest that this retardation in the reappearance of further developed cells is caused by a delay in the production of developed cells in spermatogonia in an increasing fraction of the colonies after higher neutron doses. Even in fully developed colonies the production of differentiating spermatogenetic cell types was subnormal after 300 and 350 rad. This was caused by an extensive cell degeneration in the colonies as well as by a tendency of the undifferentiated and/or A1-spermatogonial population to increase its own number at the cost of the production of further developed cells.
在CBA小鼠睾丸的组织切片中，研究了在接受150、300和350拉德中子剂量后存活的干细胞所产生的生精细胞集落的纵向生长情况，持续观察了30周。采用了两种方法：（1）再殖指数（RI），作为衡量每个睾丸中总集落长度的指标；（2）在300拉德照射后4周和15周以及350拉德照射后15周，对连续切片的睾丸中所有集落的个体长度进行测量。在150、300和350拉德照射后，集落的平均初始生长分别在8、15和20周内呈线性。尽管在这些剂量后，平均初始集落生长速率没有显著差异（约27微米/天），但两种方法均显示，在350拉德照射后，集落生长速度减慢约20%。对单个集落的筛选显示，每个睾丸中集落长度存在很大差异，且随着中子剂量增加，短集落的频率更高。在300拉德照射后对集落进行计数表明，所有存活的干细胞在照射后4周内均已开始形成集落。在用于RI测定的再殖小管切片以及单个集落的连续切片中，研究了100、150、300和350拉德照射后生精细胞向成熟精子的发育情况。尽管在300和350拉德照射后，年轻精母细胞阶段之后的生精细胞类型在1周后重新出现，但我们发现照射后连续生精细胞类型的正常重新出现没有受到很大干扰。然而，从对单个集落的研究来看，即使在一个睾丸内，集落在发育方面也存在很大差异。此外，350拉德照射后发育较差的集落频率高于300拉德照射后。我们的数据表明，在较高中子剂量后，进一步发育细胞重新出现的延迟是由于在越来越多的集落中，精原细胞中发育细胞的产生延迟所致。即使在完全发育的集落中，在300和350拉德照射后，分化生精细胞类型的产生也低于正常水平。这是由于集落中广泛的细胞退化以及未分化和/或A1精原细胞群体倾向于以进一步发育细胞的产生为代价增加自身数量所致。
