All Brawn and No Pain?
Research into the mechanistic effect of CBD on muscle recovery is lacking, but a recent study suggests it could reduce inflammation without hampering tissue regeneration
Many athletes have touted the benefits of CBD for reduction of pain and/or boosting muscle recovery, but there’s been little scientific research into exactly how this (anecdotal) effect might work. Other over-the-counter drugs taken to reduce inflammation, such as NSAIDs, have been shown to decrease satellite cell proliferation and anabolic signaling, indicating that long-term use may hamper adaptation to exercise and muscle growth. To provide more scientific evidence into the mechanistic action of CBD in skeletal muscle, Henning Langer and colleagues studied its effects in rats (1); unlike other drugs, CBD appeared to provide some modest analgesic and anti-inflammatory effects without limiting muscle recovery.
Next, to get a better mechanistic insight into how CBD could exert its effects in humans, the team turned to muscle cell culture – specifically, C2C12 myotubes (2). Overall, their results showed that CBD had only a small effect on both anabolic and inflammatory signaling in vitro. Here, Langer tells us more about the research.
What are the implications of your findings? Any surprises?
Well, it looks unlikely that CBD exerts direct effects on skeletal muscle – and that means the modest effects we found in our previous study on animals are likely to be a function of indirect signaling. For example through an effect on the central nervous system – where CBD receptors are a lot more abundant – or through circulating cells, such as macrophages.
We hypothesized that, if anything, the small effect that we found in vivo in our rats would be a little exacerbated in vitro. But that was not the case. Instead we found that there was no direct effect of CBD on the cells. As our initial hypothesis was proven wrong, I guess you could say we were slightly surprised!
How could CBD exert indirect effects in vivo through modulation of immune cells?
Immune cells are known to infiltrate skeletal muscle after injury (including intense exercise) to cause an inflammatory response. So if CBD does indeed influence this phenomenon, it could do so either by affecting the abundance of immune cells or by mediating the degree to which the immune cells send inflammatory signals to muscle tissue. However, the immune response to injuries is largely physiological and necessary to initiate repair, so it would be important that the effect of inflammation does not come at the expense of hampered regeneration of tissue. In our previous study in animals, we found the first (modest) evidence that CBD could have such properties, but we need longer studies before we can draw any firm conclusions.
Were you surprised that CB1 receptors were difficult to detect in muscle cells?
We know that CBD and other cannabinoids exert their effects primarily through central nervous system tissue, so the finding that one of the main receptors was more abundant there than in muscle was not necessarily surprising – and it has been shown by other groups before. But we were a little surprised that the difference between brain and muscle tissue was so pronounced that we had issues detecting any CB1 in muscle. Of course, technical limitations of the methods we used could be partially responsible for this, but it is still important to keep in mind when thinking about the ways cannabinoids affect peripheral tissues.
Do you plan on continuing this work in the future?
Definitely. It is a novel and exciting field to work in, and we have multiple projects running that explore some of the (many) remaining questions.
Image Credits: Ryan Lange / Unsplash.com and Simone Pellegrini / Unsplash.com
By the time I finished my degree in Microbiology I had come to one conclusion – I did not want to work in a lab. Instead, I decided to move to the south of Spain to teach English. After two brilliant years, I realized that I missed science, and what I really enjoyed was communicating scientific ideas – whether that be to four-year-olds or mature professionals. On returning to England I landed a role in science writing and found it combined my passions perfectly. Now at Texere, I get to hone these skills every day by writing about the latest research in an exciting, creative way.