Cortical Spreading Depression Denotes Concussion Injury.

Area of Science:

• Neuroscience
• Traumatic Brain Injury Research
• Concussion Studies

Background:

• Cortical spreading depression (CSD) is known after moderate-to-severe traumatic brain injury (TBI).
• Its occurrence and relation to pathology after mild, concussive TBI remain unclear.
• Understanding CSD in mild TBI is crucial for assessing brain injury and predicting outcomes.

Purpose of the Study:

• To investigate if CSD occurs after mild, concussive TBI.
• To determine the relationship between CSD, brain pathology (cell death, microbleeds), and functional deficits.
• To evaluate CSD as a potential marker for concussion severity.

Main Methods:

• Male C57BL6/J mice underwent closed head TBI (25g or 50g weight drop) or sham injury.
• Cerebral blood flow dynamics were monitored using Laser Doppler flowmetry and optical intrinsic signal imaging.
• Cell death (TUNEL) and cerebral microbleeds (Prussian blue) were assessed, alongside functional deficits at multiple time points.

Main Results:

• CSD occurred in 58.9% of mice subjected to a 50g TBI, but not in those with 25g TBI.
• Mice with CSD showed significantly higher rates of apoptotic cells and more microbleeds in the injured hemisphere compared to those without CSD.
• CSD was associated with significantly impaired functional recovery at 24 and 48 hours post-injury.

Conclusions:

• The incidence of CSD after mild TBI is dependent on impact severity.
• CSD in mild TBI is linked to increased brain pathology and worse functional outcomes.
• Concussive CSD may serve as a valuable biomarker for concussion severity, aiding in outcome prediction and therapeutic decisions.