Activating Cannabinoid Receptors Reduced Brain Damage After Bleeding Strokes in Mice | Research

The takeaway

The cannabinoid receptor agonist WIN55,212-2 reduced hematoma size, brain swelling, blood-brain barrier damage, and motor impairment after intracerebral hemorrhage in mice by suppressing two key inflammatory pathways.

Stroke researchers and neuroscientists studying neuroprotection and neuroinflammation.

Cannabinoid treatment reduced hematoma, edema, and motor impairment

What the researchers found

WIN55,212-2 treatment after intracerebral hemorrhage significantly reduced hematoma formation, brain edema, blood-brain barrier disruption, and motor impairments. The mechanism involved suppression of both NOX-2 (a major source of damaging reactive oxygen species) and the NLRP3 inflammasome (a key driver of neuroinflammation). Pharmacological NLRP3 inhibition with MCC950 also reduced hemorrhagic brain damage.

Why it matters

Intracerebral hemorrhage is a devastating stroke subtype with limited treatment options. This study identifies two specific inflammatory pathways that cannabinoid receptor activation can suppress, providing a mechanistic basis for potential therapeutic development.

The numbers in context

WIN55,212-2 reduced hematoma volume, edema, and BBB disruption in treated vs untreated ICH mice. Both NOX-2 activity and NLRP3 expression were elevated after ICH and reduced by cannabinoid treatment. MCC950 (NLRP3 inhibitor) independently reduced hematoma size, edema, and motor impairment.

How the study worked

Male C57BL/6 mice received intracerebral hemorrhage via collagenase injection, followed by intraperitoneal WIN55,212-2 and/or the NLRP3 inhibitor MCC950. Outcomes included motor activity, hematoma volume, brain water content, and blood-brain barrier permeability (Evans blue assay). NOX activity and protein levels of CB1, gp91phox, NLRP3, AQP4, and caspase-1 were measured by western blot.

What this study cannot tell us

Mouse ICH model (collagenase injection) is an approximation of human hemorrhagic stroke. WIN55,212-2 activates both CB1 and CB2 receptors, so the specific receptor contribution is unclear. Only male mice were used. The therapeutic window for treatment was not extensively explored.

How to read the evidence

Well-controlled animal study with multiple outcome measures and mechanistic investigation. Preliminary evidence requiring validation in larger models and eventually human trials.

When this study was published

Published in 2025.

The bigger picture

The endocannabinoid system has shown neuroprotective properties in traumatic brain injury, ischemic stroke, and now hemorrhagic stroke. The convergence on NOX-2 and NLRP3 as targets provides a clear mechanistic framework that could guide drug development for acute brain injuries.

Questions still open

Would CB2-selective agonists (avoiding CB1 psychoactive effects) be equally protective? Could this approach work in combination with existing stroke treatments? What is the therapeutic time window after hemorrhage?

Common questions

Could cannabis help after a stroke?

This study used a targeted cannabinoid receptor agonist, not cannabis itself. While the results are promising for drug development, smoking cannabis after a stroke would not replicate these controlled laboratory conditions and could be harmful.

What are NOX-2 and NLRP3?

NOX-2 is an enzyme that generates reactive oxygen species (free radicals) that damage brain tissue. NLRP3 is an inflammasome complex that activates inflammatory cascades. Both are major drivers of secondary brain damage after hemorrhagic stroke.

Read the original research

Cannabinoid Receptors Reduced Early Brain Damage by Regulating NOX-2 and the NLRP3 Inflammasome in an Animal Model of Intracerebral Hemorrhage.

CNS neuroscience & therapeutics, 31(4), e70385

View on PubMed ↗Publisher’s paper ↗

Citation

Martínez-Torres, Ari Misael; Ramírez-Celis, Crisalde; Morán, Julio. (2025). Cannabinoid Receptors Reduced Early Brain Damage by Regulating NOX-2 and the NLRP3 Inflammasome in an Animal Model of Intracerebral Hemorrhage.. CNS neuroscience & therapeutics, 31(4), e70385. https://doi.org/10.1111/cns.70385