Annexin A3 expression after stroke in the aged rat brain

Area of Science:

• Neuroscience
• Molecular Biology
• Pathology

Background:

• Cerebral ischemia, or stroke, triggers complex cellular responses aimed at functional recovery.
• Identifying novel proteins involved in post-stroke recovery is crucial for developing targeted therapies.
• Age-related differences in stroke recovery mechanisms remain incompletely understood.

Purpose of the Study:

• To identify novel protein candidates involved in functional recovery following cerebral ischemia.
• To investigate the expression patterns and cellular sources of identified proteins in young and aged rats post-stroke.

Main Methods:

• Middle cerebral artery (MCA) occlusion model in young and aged male rats.
• Proteomic analysis using two-dimensional polyacrylamide gel electrophoresis and mass spectrometry.
• Validation of protein expression using western blotting, real-time PCR, and immunohistochemistry.
• Double staining for cellular localization and proliferation markers.

Main Results:

• Annexin A3 (ANXA3) was identified as a significantly upregulated protein in the peri-infarct brain tissue post-ischemia.
• ANXA3 expression was confirmed to be elevated in the peri-infarct area at 3 and 14 days post-stroke in both young and aged rats.
• Immunohistochemistry revealed that ANXA3 is primarily produced by activated microglial cells.
• Aged rats exhibited increased proliferation of ANXA3-expressing cells compared to young rats.
• ANXA3-positive cells were observed in proximity to neurons, suggesting a role in neuronal debris clearance.

Conclusions:

• Annexin A3 (ANXA3) is a novel protein upregulated in the brain following cerebral ischemia.
• Activated microglia are the main source of ANXA3 in the post-stroke environment.
• Increased ANXA3 expression and proliferation in aged rats may indicate an altered inflammatory or clearance response.
• ANXA3 may play a role in the removal of dying neurons after stroke, potentially contributing to functional recovery.