Pilot study to assess visualization and therapy of inflammatory mechanisms after vessel reopening in a mouse stroke...

Area of Science:

• Neuroscience
• Immunology
• Medical Imaging

Background:

• Secondary inflammatory processes can exacerbate cerebral damage following reperfusion therapy in stroke patients.
• Understanding and mitigating these inflammatory responses is crucial for improving stroke treatment outcomes.

Purpose of the Study:

• To investigate the effects of intra-arterial anti-inflammatory therapy using tacrolimus in a mouse model of middle cerebral artery occlusion (MCAO) after reperfusion.
• To assess the impact of tacrolimus on infarct volume, blood-brain barrier integrity, and inflammatory cell infiltration.

Main Methods:

• A middle cerebral artery occlusion (MCAO) mouse model was established, followed by reperfusion and intra-arterial administration of tacrolimus or NaCl.
• Magnetic resonance imaging (MRI), including perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI), was used to assess lesion volume and blood-brain barrier permeability (using Bis-5HT-DTPA contrast agent).
• Immunohistochemical analysis was performed to quantify neutrophils, MPO-positive cells, and microglia (M1/M2 phenotypes).

Main Results:

• Tacrolimus treatment significantly reduced the apparent diffusion coefficient (ADC) lesion volume compared to the NaCl control group within 24 hours post-MCAO.
• Significantly lower enhancement of Bis-5HT-DTPA was observed in the tacrolimus group, indicating improved blood-brain barrier integrity.
• No significant differences in neutrophil, MPO-positive cell, or microglia counts were found between the groups, suggesting a potential reduction in MPO activity without altering cell numbers.

Conclusions:

• Intra-arterial administration of tacrolimus following reperfusion in a MCAO mouse model effectively reduced infarct volume and improved blood-brain barrier integrity.
• These findings suggest that anti-inflammatory agents administered intra-arterially may enhance the efficacy of mechanical thrombectomy in stroke treatment by reducing infarct size and MPO activity.
• Further research is warranted to explore the therapeutic potential of intra-arterial anti-inflammatory strategies in clinical stroke management.