Inducing Blood Clot Formation in the Mouse Brain Using a Photosensitive Dye

Take an anesthetized mouse having a cranial window with a thin skull layer to enable brain visualization with minimal invasiveness.

Under a microscope, identify an artery based on the blood flow from larger to smaller vessels. 

Inject a photosensitive dye into the tail vein that reaches the brain via circulation.

Excite the dye with light to emit fluorescence, enabling blood flow monitoring.

Increase the light intensity to induce clot formation, known as photothrombosis.

The dye absorbs high-intensity light, reacts with oxygen, and generates reactive oxygen species, which damage endothelial cells. 

The damaged cells release mediators that cause platelets to adhere, initiating clot formation. Fibrin in the blood helps entrap additional blood cells, creating a clot.             

The clot, detected by the accumulation of dye preceding it, obstructs blood flow to the brain.

Close the incision, apply antibiotics to prevent infection, and administer analgesics to reduce pain and allow recovery.