Modeling Photothrombotic Stroke in Mouse Model: A Laser Illumination Technique Through Mouse Skull Following Photosensitive Dye Administration to Induce Photothrombosis

To begin, stabilize an anesthetized mouse in a stereotactic unit. Attach a probe to monitor the mouse’s temperature. Regulate its body temperature using a heating pad.

Next, sterilize the surgical site and make a longitudinal incision to expose the skull.

Scrape off the underlying periosteum - a connective tissue layer from the skull surface.

Identify the coronal suture and mark the position of interest from the bregma - the point of intersection of the coronal and sagittal sutures.

Fix a tape with a small aperture on the marked region to restrict the exposed area during laser illumination. Now, inject the desired photosensitive dye into the peritoneal cavity of the mouse.

The injected dye molecules travel through the circulatory system and reach the brain.

Next, position the appropriate laser source above the marked region and illuminate the area for the desired duration. Following illumination, the circulating dye is activated and produces highly reactive oxygen species. These act by damaging endothelial cell membranes in the blood vessels in the illuminated area.

The endothelial cell damage promotes local activation and aggregation of platelets and subsequent thrombi formation, interrupting local cerebral blood flow. Thereafter, rehydrate the skull using saline. Close the surgical incision and return the mouse to its cage.

The interruption of cerebral blood flow damages the brain tissue, leading to dysfunction of the brain in the mouse.