Chemical compounds found in marijuana can help treat multiple sclerosis-like diseases in mice by preventing inflammation in the brain and spinal cord, according to a study reported in the Journal of Neuroimmune Pharmacology.
"Inflammation is part of the body's natural immune response, but in cases like MS, it gets out of hand," says Dr. Ewa Kozela of Tel Aviv University, Israel.
"Our study looks at how compounds isolated from marijuana can be used to regulate inflammation to protect the nervous system and its functions."
Dr. Kozela and colleagues set out to see if the known anti-inflammatory properties of two substances found in marijuana - the cannabinoids known as tetrahydrocannabinol (THC) and cannabidiol (CBD) - could also be applied to the treatment of inflammation associated with MS.
With either THC or CBD, the researchers treated immune cells that specifically target and harm the brain and spinal cord. In response to both chemicals, the immune cells, isolated from paralyzed mice, produced fewer inflammatory molecules, particularly interleukin 17 (IL-17).
Interleukin 17 "is strongly associated with MS and very harmful to nerve cells and their insulating covers," the researchers say. They conclude:
"The presence of CBD or THC restrains the immune cells from triggering the production of inflammatory molecules, and limits the molecules' ability to reach and damage the brain and spinal cord."
Medicinal benefits of CBD
THC was discovered in marijuana by scientists in Israel in 1964, and about 70 cannabinoids - compounds that are unique to cannabis, with interesting biological effects - have been identified since.
Professor Zvi Vogel, co-author of the present study, was among the first researchers to describe endocannabinoids in the 1990s, molecules that act like THC in the body.
Cannabidiol is the most plentiful and potent cannabinoid in marijuana, the Tel Aviv University researchers say. They are particularly interested in CBD "because it offers medicinal benefits without the controversial mind-altering effects of THC."
In a 2011 study, they showed that CBD helps treat MS-like symptoms in mice by preventing immune cells attacking nerve cells in the spinal cord.
For this previous work, the researchers injected mice that had an MS-like condition and partially paralyzed limbs, with CBD. The animals regained movement, "first twitching their tails and then beginning to walk without a limp."
The researchers noted that the mice treated with CBD had much less inflammation in the spinal cord than their untreated counterparts, and this led to the present study, which they want to build on toward possible treatment for humans.
Quests to find a treatment for MS continue
Further research is needed to prove the effectiveness of cannabinoids in treating MS, although the researchers note that in many countries, CBD and THC are already used for symptoms, including pain and muscle stiffness.
"When used wisely, cannabis has huge potential," Dr Kozela says. "We're just beginning to understand how it works."
The warning is not to use resveratrol supplements for MS after a study found "detrimental effects in some disease conditions and should be discouraged for supplemental use by MS patients pending further research."