A Mouse Model of Single and Repetitive Rotational Closed Head Concussive Brain Injury

Area of Science:

• Neuroscience
• Neurology
• Biomedical Engineering

Background:

• Concussive brain injury (CBI) is common but poorly understood, with repetitive injuries potentially leading to neurodegeneration like CTE.
• Existing models often lack reproducibility or cause significant structural damage, limiting insights into subtle pathological changes.

Purpose of the Study:

• To establish a reproducible mouse model of closed-head rotational brain injury that mimics key biomechanical and pathological features of human CBI.
• To investigate subtle neurovascular, inflammatory, and blood-brain barrier alterations in the absence of overt structural pathology.

Main Methods:

• Utilized a stereotactically guided electromagnetic impactor with a silicone cap to deliver standardized rotational strikes to the intact skull of conscious mice under light sedation.
• Assessed structural brain integrity using in vivo T2-weighted MRI and ex vivo histological analyses.
• Ensured minimal variability through controlled head positioning and use of medetomidine for light sedation.

Main Results:

• The model reliably induced reproducible rotational head motion without skull fractures or overt tissue disruption.
• Histological analysis revealed no tissue disruption, contusion, or microbleeds, but showed mild, widespread disruption of the microvascular interface.
• In vivo MRI confirmed the absence of gross structural damage.

Conclusions:

• This novel rotational closed-head brain injury model provides a robust platform for studying the subtle pathophysiology of concussion.
• It enables longitudinal investigations into neurovascular, inflammatory, and blood-brain barrier changes crucial for understanding concussion and repetitive injury.
• Facilitates the development of clinical biomarkers for concussion and related neurodegenerative conditions.