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Updated: Jul 20, 2026
Electromagnetic Controlled Closed-Head Model of Mild Traumatic Brain Injury in Mice
Published on: September 28, 2022
Differential behavioral and histopathological responses to graded cortical impact injury in mice
Kathryn E Saatman1, Kristofer J Feeko, Rebecca L Pape
1Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536-0509, USA. k.saatman@uky.edu
Abstract:
Controlled cortical impact (CCI) injury, a model of contusive brain injury in humans, is being used with increasing frequency in mice to investigate post-traumatic cell damage and death and to evaluate treatment strategies. Because cellular injury mechanisms and therapeutic approaches may depend on the severity of the initial insult, it is important to utilize a model in which outcomes are sensitive to injury severity. Adult male C57Bl/6 mice were anesthetized and subjected to sham injury (n = 23) or CCI injury at either 0.5 mm (n = 22) or 1.0 mm (n = 22) depth of impact at a velocity of 5 m/sec. At 2 days, brain-injured mice exhibited significant memory (p < 0.05) and motor function (p < 0.001) deficits compared to sham-injured mice; furthermore, mice subjected to an impact of 1.0 mm were significantly more impaired in both outcome measures than those injured at 0.5 mm (p < 0.05). The cortical lesion increased in size between 24 h and 7 days in both injury groups, but was significantly larger in the 1.0 mm group. Hippocampal cell loss was observed in the hilar and CA3 regions in both groups, and in the CA1 and dentate granule cell layers in the 1.0 mm group. Regional patterns of IgG extravasation and reactive astrocytosis were similar in the two injured groups, but changes were more persistent in the 1.0 mm group. Both levels of injury resulted in acute loss of neuronal MAP-2 immunoreactivity in the cortex and sub-region specific changes in the hippocampus. Thus, increasing the depth of impact led to similar structural alterations in neurons, astrocytes and the vasculature, but resulted in greater behavioral deficits and cortical and hippocampal cell death.
Insights
Controlled cortical impact (CCI) injury severity in mice impacts memory and motor function. Deeper CCI impacts cause greater behavioral deficits and cell death, highlighting the importance of injury severity in brain injury models.
Area of Science:
- Neuroscience
- Traumatic Brain Injury Research
- Animal Models of Neurological Disease
Background:
- Controlled cortical impact (CCI) is a common mouse model for studying contusive brain injuries.
- Understanding the relationship between injury severity and outcomes is crucial for evaluating treatment strategies.
Purpose of the Study:
- To investigate the impact of varying controlled cortical impact (CCI) injury depths on behavioral deficits and neuropathological outcomes in mice.
- To determine if CCI outcomes are sensitive to the severity of the initial insult.
Main Methods:
- Adult male C57Bl/6 mice underwent sham injury or CCI at 0.5 mm or 1.0 mm impact depth.
- Behavioral tests (memory and motor function) were assessed at 2 days post-injury.
- Histological analyses examined cortical lesion size, hippocampal cell loss, IgG extravasation, and MAP-2 immunoreactivity at various time points.
Main Results:
- Both 0.5 mm and 1.0 mm CCI groups showed significant memory and motor deficits compared to sham controls.
- Mice with 1.0 mm CCI exhibited more severe behavioral impairments and larger cortical lesions than the 0.5 mm group.
- Increased CCI depth led to greater hippocampal cell loss, including CA1 and dentate granule cells, and more persistent neuroinflammation markers.
Conclusions:
- Increasing the depth of controlled cortical impact injury in mice results in dose-dependent increases in behavioral deficits and neuropathological damage.
- The CCI model demonstrates sensitivity to injury severity, making it valuable for studying traumatic brain injury mechanisms and testing therapeutics.
