Researchers from the State University of Maringá and the University of Sao Paulo were able to create an artificial system that reduced blood flow to the brain in laboratory rats, simulating a common type of stroke – a transient global cerebral ischemia (TGCI).
During a TGCI, the brain loses adequate access to oxygen-rich blood. Over time, this can cause brain cells can become damaged or even die.
In both humans and animals, TGCIs can lead to a range of common stoke symptoms “such as cognitive impairments, spatial/temporal disorientation, and deficits in learning, memory, and attention,” the research team explained in their study.
If circulation is restored quickly, symptoms are usually brief, but if the stroke happens over a longer period of time, the damage can become permanent.
Using a series of memory and biochemical tests, researchers found that when CBD is taken before and after a stroke, it can protect rats from common after-effects, like memory loss and brain damage.
CBD Reduced Memory Loss in Rats After Stroke
In the study, researchers trained rats for 10 days on how to navigate to a specific location in a maze with 8 separate pathways. Animals capable of solving the maze were then given either CBD or a placebo before experiencing an artificial TGCI stroke.
“These results indicate that TGCI caused persistent retrograde amnesia, despite some degree of improvement,” the study authors explained.
Not surprisingly, animals in the placebo group all experienced memory loss – a common stroke symptom – and had significant difficulties navigating the maze even after 7 days of recovery. These rats took both longer to find the goal location and made more mistakes during their journey.
While memory slowly improved after an additional 7 days of recovery, researchers found that rats who experienced a stroke still took longer to solve the maze than healthy rats.
However, for the animals who were given CBD daily both before and after the stroke, their navigation time was surprisingly similar to the trained healthy animals, indicating that CBD can help prevent memory loss.
CBD had the same beneficial effect when the experiment was performed on another set of animals using a different memory test where rats were trained to recognize objects placed in familiar locations.
“[Animals in the placebo group] did not retain memory of the familiar location that was learned during training,” the authors said in their study. “[But] this effect of TGCI was alleviated by CBD treatment.”
CBD Reduced Brain Damage in Rats After Stroke
To see whether CBD had physical effects on the brain, the research team also examined brain samples from the animals using a series of biochemical tests.
Even after 15 days of recovery, researchers found that rats who experienced the stroke had lost a significant amount of brain cells in their hippocampus – an area of the brain involved in learning and memory.
However, rats that were given CBD daily both before and after experienced much less damage.
Additional tests also found that animals given CBD before and after the stroke had higher levels of a brain protein called: brain-derived neurotrophic factor.
Researchers explained that the protein has been previously shown to “contribute to learning and memory processes” and may help in stroke recovery.
It’s not clear yet why CBD is helping, but some possible explanations could be that CBD directly prevents brain cells from dying or may help new brain cells form after losing old ones.
Nonetheless, new treatment options are desperately needed for stroke patients. The research team explained that “no safe and effective pharmacological therapy has yet been discovered that can treat cognitive impairments that are caused by cerebral ischemia.”
The research team said that additional research into how CBD works to prevent memory loss and brain damage after strokes in animals may help develop new treatment options for human patients.
Calvin Chan is a researcher and medical writer from Edmonton, Canada. As a big science nerd, he loves reading and writing about everything science - from cannabis to dark matter and even alien life. Calvin has a PhD from the University of Alberta.