Repeated blast exposures cause brain DNA fragmentation in mice

Area of Science:

• Neuroscience
• Biochemistry
• Trauma Research

Background:

• Blast-induced traumatic brain injury (TBI) pathophysiology and behavioral deficits remain poorly understood.
• Understanding injury mechanisms is crucial for developing effective countermeasures against neurotrauma.
• Cellular DNA integrity is vital for cell function and survival.

Purpose of the Study:

• To investigate the impact of repeated blast exposures on brain DNA integrity.
• To assess cell-free DNA (CFD) in plasma as a biomarker for diagnosing and prognosing blast-induced polytrauma.
• To explore the cellular mechanisms underlying blast-induced brain injury.

Main Methods:

• Evaluation of time-dependent DNA damage in various brain regions post-blast.
• Measurement of plasma CFD levels at different time points after blast exposure.
• Assessment of mitochondrial membrane potential, cytochrome C release, and caspase-3 activity.

Main Results:

• Significant, time-dependent breakdown of cellular DNA in the brain, peaking at 24 hours post-blast.
• Transient increase in plasma CFD levels, peaking at 2 hours and returning to baseline by 24 hours, largely independent of brain DNA damage severity.
• Correlation between righting reflex recovery time and plasma CFD levels at 2 hours.
• Blast-induced brain DNA damage linked to decreased mitochondrial membrane potential, increased cytochrome C release, and elevated caspase-3, indicating apoptosis.

Conclusions:

• Repeated blast exposures cause DNA damage and initiate mitochondrial-driven apoptosis in the brain.
• Plasma CFD shows potential as a transient biomarker for blast-induced polytrauma.
• Therapeutic strategies targeting DNA damage inhibition or repair may offer effective countermeasures for blast-induced TBI.