Davison F D, Groves M, Scaravilli F
Department of Neuropathology, Institute of Neurology, Queen Square, London, UK.
Histochem J. 1995 Dec;27(12):983-8.
The technique of DNA in situ end-labelling (ISEL) for the detection of apoptotic cells has recently become the method of choice. The incorporation of a labelled nucleotide to facilitate detection into the single-stranded region of DNA cleaved by endogenous nucleases has proved to be a sensitive and straightforward technique. Previous reports have applied the technique to the study of apoptotic cells in brain tissue, which is normally subjected to relatively long-term formalin fixation. In this study we have examined the effects of long-term formalin fixation on the ability to detect apoptosis using ISEL in a variety of pathologies and in a normal rat testis. In the tissues which had been treated with overnight formalin fixation, apoptotic cells were readily identified in those pathologies where it might be expected to occur. However, in tissue which had been fixed for several weeks or more, apoptotic cells were not detectable. Samples of brain lymphoma tissue and rat testis subjected to a prospective analysis with respect to fixation time showed that the ability to detect apoptotic cells tailed off at around 3-5 weeks. In order to obviate the risk of false negative results it would be desirable to use ISEL in tissues formalin fixed for less than this period.
用于检测凋亡细胞的DNA原位末端标记（ISEL）技术近来已成为首选方法。将标记的核苷酸掺入到由内源性核酸酶切割的DNA单链区域以利于检测，这已被证明是一种灵敏且简便的技术。先前的报告已将该技术应用于脑组织中凋亡细胞的研究，脑组织通常要经过相对长期的福尔马林固定。在本研究中，我们检测了长期福尔马林固定对在各种病理状态下以及正常大鼠睾丸中使用ISEL检测凋亡的能力的影响。在经过过夜福尔马林固定处理的组织中，在可能出现凋亡细胞的那些病理状态下很容易识别出凋亡细胞。然而，在固定了数周或更长时间的组织中，无法检测到凋亡细胞。对脑淋巴瘤组织和大鼠睾丸样本就固定时间进行的前瞻性分析表明，检测凋亡细胞的能力在大约3 - 5周时开始下降。为了避免假阴性结果的风险，在福尔马林固定时间少于此期限的组织中使用ISEL是可取的。
