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Updated: Aug 5, 2026
Microvascular Embolism Mouse Model for In Vivo Two-photon Microscopy Using Fluorescent Polystyrene Microspheres
Published on: November 21, 2025
A reproducible rat model of microembolic brain injury using percutaneous coaxial microcatheter delivery of zirconia
Kentaro Kasa1, Hiroki Ohta2, Teppei Komatsu3
1Division of Vascular Surgery, Department of Surgery, The Jikei University School of Medicine, Tokyo, Japan; Division of Regenerative Medicine, Research Center for Medical Sciences, The Jikei University School of Medicine, Tokyo, Japan.
Background:
Cerebral microembolism contributes to silent brain infarction and procedure-related ischemic brain injury during catheter-based endovascular interventions. However, reproducible experimental platforms simulating particulate embolization under endovascular conditions remain limited.
New Method:
We developed a rat model of microembolic brain injury using percutaneous coaxial microcatheter delivery of zirconia beads under fluoroscopic guidance. Zirconia beads (15 µm) were loaded as a sedimented column in iodinated contrast medium within an inner microcatheter, advanced coaxially through an outer microcatheter, and delivered selectively to the left internal carotid artery (ICA) territory via the caudal ventral artery. Animals with an ICA curvature angle > 40° were excluded to reduce procedure-related variability.
Results:
Among 25 male Sprague-Dawley rats, three were excluded before embolization because of unfavorable anatomy, leaving 18 embolized rats and four sham-operated controls for analysis. The median operative time was 8.5 min (IQR, 6.3-11.0). No procedure-related mortality or significant vasospasm occurred. TTC staining at 24 h demonstrated ipsilateral infarcts in all embolized animals, with a median infarct volume of 18.7 mm³ (IQR, 15.8-24.7). No infarct lesions were observed in sham-operated animals. Infarct volume was not significantly correlated with neurological deficit score.
Comparison With Existing Methods:
Unlike conventional microsphere- or thrombus-based embolic models that typically require cervical vessel exposure and direct arterial injection, this method enables minimally invasive, fluoroscopy-guided, selective embolic delivery with angiographic monitoring and dose standardization based on catheter geometry and sediment length.
Conclusions:
This model provides a reproducible translational platform for studying microembolic brain injury and evaluating preventive or therapeutic strategies.
