The goal of this study is to evaluate the structural and behavioral changes according to different impact velocities and different deformation depths in the rat controlled cortical impact (CCI) model.

Male Sprague- Dawley rats (250-300 g) were anesthetized and traumatic brain injury (TBI) was induced by impacting the cerebral cortex using a pneumatic CCI device at the different velocities and injury depths. One day after TBI, the neurological function was assessed and then the injured area of cerebral cortex and hippocampus was measured.

With a 3.2 or 3.9 m/s of impact velocity, there was a significant decrease in rotarod motor score at 2.5 mm of deformation depth compared to 1.5 mm, and the injured area of cortex was increased significantly at 2.0 or 2.5 mm of depths compared to 1.5 mm. The injured area of hippocampus was significantly increased at 2.5 mm of depth with a 3.2 m/s of velocity and 2.0 or 2.5 mm of depths with a 3.9 m/s of velocity, compared to the other deformation depths. For the same deformation depth, only the injured area of hippocampus was significantly different between each velocity with a 2.0 mm of depth.

This study presented the neurological and morphological changes according to the various deformation parameters in the rat CCI model. We expect that our results will provide a guideline in determining those parameters for reproducible gradation of rat CCI injury.