Effect of postmortem change on development of apoptosis in rats

末端脱氧核苷酸转移酶（TdT）介导的dutp -地高辛缺口末端标记法（TUNEL）可用于原位检测凋亡细胞。我们通过血氧lin-eosin （H-E）和TUNEL实验检测了死后延迟是否影响各器官细胞凋亡信号的发展。Wistar Imamichi大鼠用x射线照射，照射6小时后处死。切除脾脏、胸腺、肾上腺和睾丸，置于室温湿室保存。分别于0、6、12、24小时后固定各组组织，制作石蜡包埋切片。未放疗组脾、胸腺、睾丸切片可见少量TUNEL阳性细胞，肾上腺未见。死后延迟未观察到凋亡细胞数量的增加。放疗组脾、胸腺TUNEL阳性细胞核深度染色明显增多，与H-E切片核缩小区相对应。睾丸切片阳性染色细胞数略有增加，H-E切片未见变化。随着死后时间的延迟，TUNEL阳性细胞边缘由清晰变为模糊，阳性区向四周扩散。我们的结果表明，很难区分凋亡细胞和死后变化。然而，随着TUNEL阳性区域的扩散，可以检测到TUNEL阳性细胞的死后变化。

Terminal deoxynucleotidyl transferase (TdT) -mediated dUTP-digoxigenin nick end labeling (TUNEL) assay is useful to detect apoptotic cells in situ. We examined whether or not postmortem delay affects the development of apoptotic signals of cells in various organs by hematoxy lin-eosin (H-E) and TUNEL assay.Wistar Imamichi rats were radiated by X-ray and sacrificed six hours after radiation. The spleen, thymus, adrenal and testis were excised and kept in moist chamber at room temperature. Each tissue was fixed after different time intervals 0,6,12,24 hours, and paraffin-embedded sections were made. In no radiation group, a little of TUNEL positive cells were observed in the spleen, thymus and testis sections, but not in the adrenal. No increase in the number of apoptotic cells was observed with postmortem delay. In the radiation group, much increase in the number of TUNEL positive cells of which nuclei were clearly and deeply stained was observed in the spleen and thymus corresponding to the area where shrinking nuclei were observed in H-E section. In testis sections, there was a little increase in the number of positively stained cells, and no change was observed in H-E section. With postmortem delay, the margin of the TUNEL positive cells changed from clear to indistinct, and the positive area was spread around. Our results shows that it is difficult to distinguish apoptotic cell from postmortem change. It is possible, however, to detect TUNEL positive cell with postmortem changes as the spread TUNEL positive area.