Experimental Study Of Posttraumatic Cerebral Ischemia

Objective:Investigate the injured side of the cerebrovascular damage and the protective effect of nimodipine after fluid percussion brain injury in rats to provide experimental evidence for posttraumatic cerebral ischemia. Methods:96adult male Sprague-Dawley rats were randomly divided into injury group and nimodipine group and each of them were randomly divided into6subgroups (normal group, sham group,3h,12h,48h,120h), Each subgroup contained eight rats. Brain injury model was built up by fluid percussion injury method, The nimodipine group rats were intragastric administration of nimodipine. Applying Light microscopy to observe the trunk of the middle cerebral artery. By immunohistochemical method to detected type the IV collagen of the middle cerebral artery. Counted the circulating endothelial cells. Results:1After fluid percussion brain injury, middle cerebral arteries lumina were narrowed, endothelial cells lost, smooth muscle cells were deformation and edema; Compared with the normal groups, the expression of type Ⅳ collagen of the middle cerebral devresed in the experimental groups(P<0.05), and the number of the circulating endothelial cell increased(P<0.05).2The expression of type Ⅳ of the48h and120h subgroups in the nimodipine group is taller than the corresponding time subgroups of the injury group(P<0.05); the number of the circulating endothelial cell of the12h,48h and120h subgroups in the nimodipine group is lower than he corresponding time subgroups of the injury group(P<0.05). Conclusion:1After fluid percussion brain injury, the structure of the middle cerebral artery is changed:the injury and apoptosis of endothelial cells, the edema of smooth muscle cells; the expression of type Ⅳ decreased and the number of the circulating endothelial cells increase. These results suggest that there are changes of the structure and function in large intracranial vascularchanges and the injury of vascular endothelial cells.2Nimodipine could improved the expression of collagen type IV and reduce the number of number of the circulating endothelial cells. These results suggest that nimodipine can protect the cerebral blood vessel especially the endothelial cells after fluid percussion brain injury.