Extremely low doses of marijuana’s psychoactive component can protect the brain before and after injury, according to Tel Aviv University Prof. Yosef Sarne.
Medical cannabis is often used by sufferers of chronic ailments, including cancer and post-traumatic stress disorder, to combat pain, insomnia, lack of appetite, and other symptoms but has not been identified as being able to prevent damage to the body.
Prof. Sarne of the Adelson Center for the Biology of Addictive Diseases says that the drug has neuroprotective qualities and that extremely low doses of THC – the psychoactive component of marijuana – protects the brain from long-term cognitive damage in the wake of injury from lack of oxygen, seizures, or toxic drugs. Brain damage can have consequences ranging from mild cognitive deficits to severe neurological damage.
Previous studies focused on injecting high doses of THC within a very short time frame of approximately 30 minutes before or after injury. Prof. Sarne’s current research, published in the journals Behavioural Brain Research and Experimental Brain Research, demonstrates that even extremely low doses of THC around 1,000 to 10,000 times less than that in a conventional marijuana cigarette and administered over a wide window of up to seven days before or one to three days after injury can jumpstart biochemical processes which protect brain cells and preserve cognitive function over time.
This treatment, especially in light of the long time frame for administration and the low dosage, could be applicable to many cases of brain injury and be safer over time, Prof. Sarne says.
In the lab, the researchers injected mice with a single low dose of THC either before or after exposing them to brain trauma. A control group of mice sustained brain injury but did not receive the THC treatment. When the mice were examined three to seven weeks after initial injury, recipients of the THC treatment performed better in behavioral tests measuring learning and memory. Additionally, biochemical studies showed heightened amounts of neuroprotective chemicals in the treatment group compared to the control group.
The use of THC can prevent long-term cognitive damage that results from brain injury, the researchers conclude. One explanation for this effect is pre- and post-conditioning, whereby the drug causes minute damage to the brain to build resistance and trigger protective measures in the face of much more severe injury, explains Prof. Sarne. The low dosage of THC is crucial to initiating this process without causing too much initial damage.
According to Prof. Sarne, there are several practical benefits to this treatment plan.
Due to the long therapeutic time window, this treatment can be used not only to treat injury after the fact, but also to prevent injury that might occur in the future.
For example, cardiopulmonary heart-lung machines used in open heart surgery carry the risk of interrupting the blood supply to the brain, and the drug can be delivered beforehand as a preventive measure. In addition, the low dosage makes it safe for regular use in patients at constant risk of brain injury, such as epileptics or people at a high risk of heart attack.
Prof. Sarne is now working in collaboration with Prof. Edith Hochhauser of the Rabin Medical Center to test the ability of low doses of THC to prevent damage to the heart.
Preliminary results indicate that they will find the same protective phenomenon in relation to cardiac ischemia, in which the heart muscle receives insufficient blood flow.