STUDIES ON PATHOLOGIC CHANGES OF CEREBRAL CONCUSSION AND APOPTOSIS OF NERVOUS CELLS IN WISTAR RATS / 解放军医学杂志

ABSTRACT

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.