Iron-induced necrotic brain cell death in rats with different aerobic capacity

Area of Science:

• Neuroscience
• Biochemistry
• Pathology

Background:

• Brain iron overload is a significant factor in brain injury following intracerebral hemorrhage (ICH).
• Previous research indicated greater ICH-induced brain injury in low capacity runner (LCR) rats than in high capacity runner (HCR) rats.

Purpose of the Study:

• To investigate whether iron-induced brain injury differs between LCR and HCR rats.
• To explore the potential mechanisms, including complement activation and membrane attack complex (MAC) formation, underlying iron-induced brain injury.

Main Methods:

• Adult male LCR and HCR rats received intracaudate injections of iron or saline.
• T2 magnetic resonance imaging was performed, followed by euthanasia at 2 and 24 hours for brain analysis.
• Immunostaining and Western blotting were utilized to assess brain injury markers, cell death, and MAC expression.

Main Results:

• LCR rats showed significantly greater hemispheric swelling, T2 lesion volumes, blood-brain barrier disruption, and neuronal death at 24 hours post-iron injection.
• Increased propidium iodide (PI)-positive cells, indicating necrotic cell death, were observed in both groups at 2 hours, with higher intensity in LCRs.
• Membrane attack complex (MAC) expression was elevated at 2 hours post-iron injection and was notably higher in LCR rats, co-localizing with PI-positive cells.

Conclusions:

• Iron induces more severe necrotic brain cell death, brain swelling, and blood-brain barrier disruption in LCR rats.
• These effects in LCR rats may be associated with complement activation and subsequent MAC formation.
• The findings highlight differential susceptibility to iron-induced brain injury based on running capacity, potentially mediated by complement pathways.