Filament Insertion-based Transient Stroke Model: A Surgical Procedure to Perform Middle Cerebral Artery Occlusion in Murine Brain

Turn the mouse to the supine position, then put the snout into the anesthesia cone, and fix the paws with tape. Disinfect the skin and hair surrounding the chest, and make a 2 centimeter long midline incision in the neck.

Use forceps to pull the skin, submandibular gland, and sternomastoid muscle apart. Use retractors to expose the surgical field and find the left common carotid artery or CCA.

Dissect the CCA free from connective tissue and surrounding nerves, without harming the vagal nerve, and perform a transient ligation before the bifurcation. Dissect the external carotid artery or ECA and tie a permanent knot at the most distal, visible part.

Place another suture under the ECA, and close to the bifurcation, then prepare a loose knot to be used later. Dissect the internal carotid artery, or ICA, and place a microvascular clip on it about 5 millimeters over the bifurcation. Make sure not to damage the vagal nerve. Then, cut a small hole into the ECA between the tight and the loose ligations, ensuring not to cut the entire ECA.

Introduce the filament and advance it towards the CCA. Tighten the loose ligation in the ECA around the lumen to momentarily secure the filament in that position, removing the microvascular clip, and prevent bleeding. After removing the microvascular clip, insert the filament through the ICA until the origin of the MCA is reached. Fix the filament in this position by further tightening the knot around the ECA. Remove the retractor and relocate the sternomastoid muscle in the submandibular gland before suturing the wound.