Methods: The graded model of rats was set up by using the dev ice of the improved fluid-percussion model, then we observed the changes of bra in tissue of rats.

• 方法：采用自行改进的液压冲击模型装置产生大鼠液压冲击脑外伤模型，对大鼠脑组织进行肉眼和光镜观察。