Yin Dali, Zhou Changman, Kusaka Ikuyo, Calvert John W, Parent Andrew D, Nanda Anil, Zhang John H
Department of Neurosurgery, University of Mississippi Medical Center, Jackson, Mississippi, USA.
J Cereb Blood Flow Metab. 2003 Jul;23(7):855-64. doi: 10.1097/01.WCB.0000073946.29308.55.
The hypothesis was tested that hyperbaric oxygen therapy (HBO) reduced brain infarction by preventing apoptotic death in ischemic cortex in a rat model of focal cerebral ischemia. Male Sprague-Dawley rats were subjected to middle cerebral artery occlusion/reperfusion (MCAO/R) and subsequently were exposed to HBO (2.5 atmospheres absolute) for 2 h, at 6 h after reperfusion. Rats were killed and brain samples were collected at 24, 48, 72 h, and 7 days after reperfusion. Neurologic deficits, infarction area, and apoptotic changes were evaluated by clinical scores, 2,3,7-triphenyltetrazolium chloride staining, caspase-3 expression, DNA fragmentation assay, and terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate-biotin nick end labeling (TUNEL)-hematoxylin and eosin (H&E) costaining. In MCAO/R without HBO treatment animals, DNA fragmentation was observed in injured cortex at 24, 48, and 72 h but not in samples at 7 days after reperfusion. Double labeling of brain slides with NeuN and caspase-3 demonstrated neurons in the injured cortex labeled with caspase-3. TUNEL+H&E costaining revealed morphologic apoptotic changes at 24, 48, and 72 h after reperfusion. Hyperbaric oxygen therapy abolished DNA fragmentation and reduced the number of TUNEL-positive cells. Hyperbaric oxygen therapy reduced infarct area and improved neurologic scores at 7 days after reperfusion. One of the molecular mechanisms of HBO-induced brain protection is to prevent apoptosis, and this effect of HBO might preserve more brain tissues and promote neurologic functional recovery.
在局灶性脑缺血大鼠模型中，检验了高压氧疗法（HBO）通过防止缺血皮质细胞凋亡死亡来减少脑梗死的假说。雄性Sprague-Dawley大鼠接受大脑中动脉闭塞/再灌注（MCAO/R），随后在再灌注后6小时暴露于HBO（绝对压力2.5个大气压）2小时。在再灌注后24、48、72小时和7天处死大鼠并收集脑样本。通过临床评分、2,3,7-三苯基氯化四氮唑染色、半胱天冬酶-3表达、DNA片段化分析以及末端脱氧核苷酸转移酶介导的生物素化脱氧尿苷三磷酸缺口末端标记（TUNEL）-苏木精和伊红（H&E）复染来评估神经功能缺损、梗死面积和凋亡变化。在未经HBO治疗的MCAO/R动物中，在再灌注后24、48和72小时在损伤皮质中观察到DNA片段化，但在再灌注后7天的样本中未观察到。用NeuN和半胱天冬酶-3对脑切片进行双重标记显示损伤皮质中的神经元被半胱天冬酶-3标记。TUNEL+H&E复染显示再灌注后24、48和72小时出现形态学凋亡变化。高压氧疗法消除了DNA片段化并减少了TUNEL阳性细胞的数量。高压氧疗法减少了再灌注后7天的梗死面积并改善了神经功能评分。HBO诱导脑保护的分子机制之一是防止细胞凋亡，HBO的这种作用可能会保留更多脑组织并促进神经功能恢复。
