大鼠实验性脑震荡的病变规律和神经细胞凋亡研究

STUDIES ON PATHOLOGIC CHANGES OF CEREBRAL CONCUSSION AND APOPTOSIS OF NERVOUS CELLS IN WISTAR RATS

采用Wistar大鼠复制脑震荡动物模型 ,于伤后 1、3、7、14及 30天活杀取脑组织 ,经光镜、电镜和原位末端标记等技术研究脑震荡的病变规律及神经细胞凋亡情况。结果显示 ,10 0g砝码于 1m处撞击大鼠头部可复制大鼠脑震荡的模型 ,其基本病变为脑血管扩张、淤血、出血、脑组织水肿 ,神经元变性、凋亡和坏死 ,尼氏体减少甚至消失。伤后 1～3天 ,脑组织呈点灶状坏死 ,周围组织疏松 ,单核及泡沫样细胞增多 ,神经元变性、凋亡和坏死。 7天脑水肿达高峰 ,海马锥体细胞减少 ,呈极度缺血性改变。 14～ 30天仍见血管扩张、淤血 ,可见出血 ,水肿好转。原位末端标记显示 ,伤后 1天见凋亡细胞增多 ,3天数量达高峰 ,伤后 30天凋亡的神经元持续存在。结果提示 ,脑震荡以血液循环障碍和实质细胞变性、凋亡和坏死为主要病理改变 ;神经细胞凋亡是脑震荡神经元迟发性损害的主要形式之一。

Altogether 80 Wistar rats were used for an animal model of cerebral concussion, which were sacrificed on days 1,3,7,14 and 30 after injury and the brain tissue was collected. The pathologic changes of cerebral concussion and apoptosis of nervous cells were studied by means of light microscopy, electron microscopy and in situ terminal end labeling method. The results showed that the clinical situation for cerebral concussion occurred in rats struck by 100g standard weight from 1 meter high. The basic pathologic changes were the cerebral vascular dilatation, congestion, hemorrhage, and edema of cerebral tissue. Nervous cells underaent degeneration, apoptosis and necrosis, and the Nissl bodies obviously decreased, even disappeared. On days 1～3 after injury, dot or piece necrosis was seen in brain tissue, around which the tissue rarefied. Monocytes and foam cells increased, and lots of neurons underwent degeneration, apoptosis and necrosis. The edema of cerebral tissue reached its peak on day 7. Hippocampal pyramidal cells decreased in number and showed the changes of obvious ischemia. On days 14～30, blood vessels also showed dilatation, congestion and hemorrhage, whereas edema alleviated. The neurons in cerebral cortex and hippocampus also showed the changes of chronic ischemia. By in situ terminal end labeling the number of apoptotic neurons increased on day 1, reached its peak on day 3 and still existed on day 30. The results suggested that the main pathologic changes of cerebral concussion were blood circulatory disorder and nervous cell degeneration, apoptosis and necrosis. Apoptosis of nervous cells was one of the main changes in cerebral concussion.