Piantadosi C A, Zhang J, Levin E D, Folz R J, Schmechel D E
Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA.
Exp Neurol. 1997 Sep;147(1):103-14. doi: 10.1006/exnr.1997.6584.
Delayed neurological damage after CO hypoxia was studied in rats to determine whether programmed cell death (PCD), in addition to necrosis, is involved in neuronal death. In rats exposed to either air or CO (2500 ppm), microdialysis in brain cortex and hippocampus was performed to determine the extent of glutamate release and hydroxyl radical generation during the exposures. Groups of control and CO-exposed rats also were tested in a radial maze to assess the effects of the CO exposures on learning and memory. At 3, 7, and 21 days after CO exposure brains were perfusion-fixed and hematoxylin-eosin (H&E) was used to assess injury and to select regions for further examination. DNA fragmentation was sought by examining cryosections with the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) reaction. We found significant increases in glutamate release and .OH generation during and immediately after CO hypoxia. CO-exposed rats showed learning and memory deficits after exposure associated with heterogeneous cell loss in cortex, globus pallidus, and cerebellum. The frontal cortex was affected most seriously; the damage was slight at Day 3, increased at Day 7, and persistent at Day 21 after CO exposure. TUNEL staining was positive at all three time points, and TUNEL-labeled cells were distributed similarly to eosinophilic cells. The number of cells stained by TUNEL was less than by H&E and amounted to 2 to 5% of all cell nuclei in regions of injury. Ultrastructural features of both neuronal necrosis and apoptosis also were observed readily by electron microscopy. These findings indicate that both necrosis and apoptosis (PCD) contribute to CO poisoning-induced brain cell death.
研究了一氧化碳（CO）缺氧后大鼠的迟发性神经损伤，以确定除坏死外，程序性细胞死亡（PCD）是否参与神经元死亡。对暴露于空气或CO（2500 ppm）的大鼠进行大脑皮层和海马的微透析，以确定暴露期间谷氨酸释放和羟基自由基生成的程度。还对对照组和CO暴露组的大鼠进行放射状迷宫测试，以评估CO暴露对学习和记忆的影响。在CO暴露后3天、7天和21天，对大脑进行灌注固定，并用苏木精-伊红（H&E）染色评估损伤情况，并选择区域进行进一步检查。通过用末端脱氧核苷酸转移酶介导的dUTP-生物素缺口末端标记（TUNEL）反应检查冰冻切片来寻找DNA片段化。我们发现，在CO缺氧期间及之后，谷氨酸释放和·OH生成显著增加。CO暴露的大鼠在暴露后出现学习和记忆缺陷，伴有皮层、苍白球和小脑的异质性细胞丢失。额叶皮层受影响最严重；CO暴露后第3天损伤轻微，第7天增加，第21天持续存在。在所有三个时间点TUNEL染色均为阳性，TUNEL标记的细胞分布与嗜酸性细胞相似。TUNEL染色的细胞数量少于H&E染色的细胞，在损伤区域占所有细胞核的2%至5%。通过电子显微镜也很容易观察到神经元坏死和凋亡的超微结构特征。这些发现表明，坏死和凋亡（PCD）均导致CO中毒诱导的脑细胞死亡。
