Aim: To explore the expression and significance of enkephalin and dopamine in rat cerebral concussion tissue.
Methods: 80 Wistar male rats were used to make animal model of cerebral concussion, which were sacrificed on 1,3,7,14 and 30 days after postconcussion and the brain tissues were taken out. The expression patterns of enkephalin and dopamine were studied in the course of cerebral concussion by immunohistochemical staining.
Results: The clinical manifestation with typical cerebral concussion character was seen in rat group with 100 g body weight. The mainly pathologic changes were cerebral vascular constriction and dilatation, congestion and edema of cerebral tissue, and neuronal degeneration and necrosis. Expression of enkephalin was increased on day 1 after injury and the enkephalin positive area was in the plasma of endothelial cells in cerebral cortex, hippocamp and cerebellum. The expression of enkephalin reached the peak on day 7 after injury, and the positive area was also seen in the plasma of neurons in cerebral cortex, hippocamp and cerebellum. From 14 days after injury, the expression of enkephalin decreased gradually, but until 30 days after injury it was still higher than that of controls. Expression of dopamine increased in 7 days after injury and the positive area was seen in the plasma of endothelial cells and in the vessel wall in cerebral cortex, hippocamp, thalamus and cerebellum, and had no notable changes at other time points.
Conclusion: The mainly pathologic changes after cerebral concussion were blood circulatory disorder and denaturation and necrosis of parenchymal cells. Enkephalin and dopamine may participate in the pathophysiological course of cerebral injury after cerebral concussion, and play an important role in the blood vessel injury, regulation of blood-brain barrier and the denaturation and necrosis of nerve cells.