Protective Effects of Cannabidiol Against Hippocampal Cell Death and Cognitive Impairment Induced by Bilateral Common Carotid Artery Occlusion in Mice

The present study investigated whether cannabidiol (CBD), a major non-psychoactive constituent of marijuana, protects against hippocampal neurodegeneration and cognitive deficits induced by brain ischemia in adult mice. Male Swiss mice were subjected to a 17 min of bilateral common carotid artery occlusion (BCCAO) and tested in the Morris water maze 7 days later. CBD (3, 10, and 30 mg/kg) was administered 30 min before and 3, 24, and 48 h after BCCAO. After behavioral testing, the brains were removed and processed to evaluate hippocampal cell survival and degeneration using Nissl staining and FluoroJade C histochemistry, respectively. Astroglial response was examined using immunohistochemistry for glial fibrillary acidic protein (GFAP). CBD (3-30 mg/kg) improved spatial learning performance in BCCAO mice. The Nissl and FJC staining results showed a decrease in hippocampal neurodegeneration after CBD (10 and 30 mg/kg) treatment. GFAP immunoreactivity was also decreased in ischemic mice treated with CBD (30 mg/kg). These findings suggest a protective effect of CBD on neuronal death induced by ischemia and indicate that CBD might exert beneficial therapeutic effects in brain ischemia. The mechanisms that underlie the neuroprotective effects of CBD in BCCAO mice might involve the inhibition of reactive astrogliosis.