Cannabis Reverses Brain Aging in Mice

Published: October 14, 2021

Narrator: Could low doses of cannabis benefit an aging brain? Evidence suggests it can, if the brain belongs to a mouse. Nearly every organ in your body (and in the bodies of mice) has receptors for endocannabinoids, molecules produced naturally by the body that are named after cannabis. Collectively, this is the endocannabinoid system, which helps regulate things like sleep, cognition, memory, and mood.

Daniele Piomelli: One of the things that we have discovered about the endocannabinoid system is the fact that it changes with age. And in old age, its activity decreases.

Narrator: Since our natural cannabinoids wane in old age, some researchers have been studying whether cannabinoids from cannabis - like THC - might have a beneficial impact for senior citizens. Well, senior mice, that is.

Like humans, mice turn gray, move slower, and perform worse on cognitive tests as they age. It’s something that’s easy to observe in a maze partly filled with a white-colored liquid, which obscures the mice’s scent trails and prevents them from seeing the exit.

Nicole Ashpole: When we take young mice and we put them in a learning and memory maze, they will very quickly learn to find the escape. Our aged mice will also learn how to escape the maze but they just don’t learn as efficiently. So it might take a young mouse 16 attempts in the maze to master it. But it might take an old mouse 25. And so we can see that the old mice can still learn. They just don’t learn as quickly.

Narrator: Researchers in Germany, Israel, and the US tried treating old mice with low doses of synthetic THC. One of the researchers is Nicole Ashpole.

Ashpole: When we treated old animals with a synthetic version of THC at low doses, we would see a stimulation effect. They would move faster, they would move more. They had increases in their ability to be able to solve the mazes more efficiently. That is consistent with what had been reported by the other groups showing really low doses could lead to a beneficial effect.

Narrator: So could low doses of cannabis improve cognition in an aging brain?

Ashpole: One of the biggest hallmarks of aging that we see that can contribute to frailty and other impairments in advanced age is increases in inflammation. Cannabis and many cannabinoids can reduce inflammation within the brain and throughout the rest of the body. And so it’s likely that when we’re administering cannabinoids that are acting as anti-inflammatory signals, that they are inherently improving the aging system by simply taking away the stressors of inflammation.

Narrator: Animal studies have demonstrated a connection between reduced inflammation and low doses of cannabis. And among a group of human patients living with HIV, a population characterized by inflammation of their central nervous systems, cannabis exposure was linked with lowered neurocognitive impairment. In addition, there’s some evidence that cannabis may be able to improve sleep quality, including in humans, which in turn can impact cognition.

Scientists are still studying THC, and whether stimulating our endocannabinoid system with cannabis compounds could help us as we get older. But some research results do seem fairly consistent: younger brains, which are still developing, are more at risk for negative impacts from THC.

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