Custom filaments for intraluminal artery occlusion models of stroke in mice

Available treatments for ischemic stroke have severe limitations and innovation is hampered by a major bench-to-bedside translational block, demanding refinement of animal models. Intraluminal filament occlusion of the middle cerebral artery (MCA) in rodents is a standard stroke model, requiring atraumatic and effective occluding filaments to fit each animal. We describe a simple and low-cost method to manufacture silicone-coated arterial occluder filaments, with accessible materials. This technique yields cylindrical silicone coatings of predictable and reproducible length and diameter, which can be adapted for different species, sizes of animals and blood vessels. 200 filaments produced with a 6–0 mononylon suture and mold-coated silicone tips were analyzed. Using PE-10 polyethylene tubing stretched to various inner diameters as molds, the silicone tips were nearly cylindrical, with average diameters ranging from 0.22 to 0.28 mm. The diameters measured along each silicone tip had a coefficient of variation of only 4.0 %. Laser Doppler showed stable blood flow reduction in the MCA territory of Swiss mice, with only 2.4 % change of flow during a 30 min occlusion. Motor deficits and corticostriatal infarcts were as expected for similar MCA stroke models. Comparison with existing methods: Unlike others, our molding procedure yielded filaments with a continuous range of diameters, which could be made to fit each mouse’s arteries and adjusted for other species. Having an assortment of custom filaments may improve the success rate and reproducibility of transient MCA occlusion, aiding in the discovery of new potential treatments for stroke. • A detailed procedure for manufacturing MCA occluder filaments is described • Molding silicone in polyethylene tubing yields cylindrical tips with desired diameter • Adjusting mold dimensions yields a continuous range of filaments diameters • Custom filaments induced stable reduction in cortical blood flow in mice • Custom filaments may fit different artery calibers, animal ages and species