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目的 探讨新生动物脑缺氧缺血 (HI)后迟发性细胞死亡是否存在细胞凋亡 ;分析不同检测手段的敏感性与特异性。方法 在建立新生大鼠脑HI损伤标准动物模型基础上 ,采用脑组织病理学HE染色光镜观察、透射电镜、原位末端标记 (ISEL)及DNA电泳等分别对HI后不同时间点的实验侧脑皮质、海马回中凋亡细胞的形态、特点等进行观察和比较。结果 光镜、电镜下显示实验侧脑皮质及海马神经元皱缩、染色质凝集并出现凋亡小体 ,ISEL及DNA电泳证实有裂解DNA存在。且发现脑皮质及海马回凋亡性细胞死亡通常自HI后 6～ 12h开始 ,2 4h达高峰。结论 缺氧缺血可引起新生动物脑细胞凋亡。在脑HI迟发性损伤中不仅存在坏死 ,而且存在着复杂的细胞凋亡过程。不同的检测手段均具有一定的局限性 ,只有结合多种方法进行检测 ,才能正确判定凋亡细胞的存在。
Objective To investigate whether there is apoptotic cell death in neonatal rats after hypoxic-ischemic brain injury (HI), and to analyze the sensitivity and specificity of different detection methods. Methods Based on the establishment of a standard animal model of HI injury in neonatal rats, the histopathology was observed by light microscopy, transmission electron microscopy, ISEL and DNA electrophoresis. Cerebral cortex and hippocampus in apoptotic cells morphology, characteristics were observed and compared. Results Light microscopy and electron microscopy showed that the cortex and hippocampal neurons in experimental side were shrunk, chromatin was aggregated and apoptotic bodies appeared. ISEL and DNA electrophoresis confirmed the presence of cleaved DNA. And found that the death of cerebral cortex and hippocampal apoptotic cells usually start 6 ~ 12h after HI, reaching the peak at 24 hours. Conclusion Hypoxia-ischemia can induce apoptosis of neonatal brain cells. Not only necrosis exists in the delayed injury of brain HI, but also has complicated process of apoptosis. Different detection methods have some limitations, and only by combining a variety of methods to detect, in order to correctly determine the existence of apoptotic cells.