Microangiographic changes following cerebral contusion in rats

The purpose of this study was to investigate the acute changes due to cerebral contusion in the large vessels and microvasculature in the rat. Thirty adult Sprague-Dawley rats underwent craniectomy performed in the left parietal region, producing a burr hole approximately 8-12 mm in diameter. The dura was left intact and a solid glass rod with a base diameter of 6 mm and weighing 5.2 g was dropped on the brain. Silicone rubber perfusion was performed at 24 h (10 rats) and 48 h (10 rats). Ten rats served as normal controls. The perfused brains were cleared using the alcohol-methylsalicylate technique. The results showed that the arterial and venous systems were clearly visualized by silicone rubber microangiography in the normal rat. Silicone rubber microangiography provided an excellent three-dimensional method for defining the distribution of the vasculature of the normal and contusioned rat brain, and was helpful in elucidating the pathophysiology of post-traumatic ischemia and hemorrhages of the brain. The brain displayed marked ischemia and hemorrhage at the contusion site. The hemorrhages were distributed throughout regions of white and gray matter at the injury site. All contusioned animals of those superficial arteries were irregularly filled or unfilled. The present study suggests that the pathogenesis of the post-traumatic brain may be related to damage of the superficial arteries and their arterial branches. Comparison of the brains from animals killed at 24 and 48 h following contusion revealed that the contusion was more severe 24 h after the vascular damage than after 48 h. Therefore, in the brains that were killed at 48 h, the contusion site was less avascular than those at the earlier times.