Early decrease in apurinic/apyrimidinic endonuclease is followed by DNA fragmentation after cold injury-induced brain...

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• Apurinic/apyrimidinic endonuclease (APE1) is vital for DNA base excision repair, particularly against reactive oxygen species-induced damage.
• Reactive oxygen species are implicated in cold injury-induced brain trauma.
• Understanding APE1's role in this trauma is crucial for developing therapeutic strategies.

Purpose of the Study:

• To investigate the protein expression of apurinic/apyrimidinic endonuclease (APE1) in the brain following cold injury-induced trauma.
• To correlate changes in APE1 expression with DNA damage and repair processes in the affected brain regions.

Main Methods:

• Immunohistochemistry was used to assess APE1 nuclear expression in mouse brains before and at various time points after cold injury.
• Western blot analysis was performed on non-ischemic brain tissue samples.
• DNA fragmentation was quantified to assess the extent of DNA damage.

Main Results:

• Control brains showed widespread nuclear APE1 expression.
• One hour post-injury, APE1 expression decreased in the lesion's inner boundary and increased in the outer boundary.
• By 4-24 hours, APE1 was largely absent in the lesion but markedly increased in the outer boundary zone; Western blots confirmed decreased APE1 levels in non-ischemic areas, and DNA fragmentation increased over time.

Conclusions:

• Cold injury-induced brain trauma leads to a rapid decrease in apurinic/apyrimidinic endonuclease (APE1) within the lesion.
• Increased APE1 at the lesion boundary suggests a localized, potentially overwhelmed, repair response.
• Early APE1 depletion and impaired DNA repair may contribute to neuronal cell death in cold injury-induced brain trauma.