Joint pain and osteoarthritis (OA) are among the leading causes of performance loss in equine athletes, affecting around 60% of the overall population. Chronic inflammation might cause permanent changes in joint function, leading to long-term pain, swelling, and decreased range of motion, among other debilitating symptoms.
Many of the current OA treatments are management tools that prolong function, generally without modifying OA progression. The most common treatments include non-steroidal anti-inflammatory drugs (NSAIDs) and oral joint supplements that target cartilage repair or protective pathways, as well as joint injections with corticosteroids or newer orthobiologics, both of which are anti-inflammatory. Unfortunately, many of these treatments are associated with other adverse effects, especially when used long-term.
Reducing Joint Inflammation With CBD
Scientists have proposed several novel treatments to reduce joint inflammation with minimal side effects, including cannabidiol (CBD), a nonpsychoactive chemical compound found in Cannabis sativa (colloquially known as hemp). CBD targets the endocannabinoid system, a complex network of several biological systems that affects many physiological processes, including pain perception, appetite, mood, learning, immune function, and more. Within the context of OA, CBD has been found to inhibit the production of substances that increase inflammation, decrease sensitivity of pain-associated receptors, and modulate an overactive immune system. Anecdotally, many people claim the benefits of CBD, but more research is required to accurately quantify and qualify its potential benefits and risks, especially for use in horses.
Studying the Impact of CBD on Equine Joint Health
Researchers at the Page Laboratory at the University of Kentucky’s Gluck Equine Research Center are implementing a three-phase project to better understand CBD’s potential anti-inflammatory effects in equine joints. The aim is to improve a chemically induced joint inflammation model such that it will be repeatable and reversible, while still accurately mimicking the body’s physical and biochemical response to inflammation.
Phase One
Phase one involves refining the dosage of a pro-inflammatory compound that will be injected into one carpal joint, inducing temporary inflammation. Defining an appropriate dosage protocol and taking note of individual horse variability is an important step for developing a reliable experimental procedure.
Phase Two
In phase two, researchers aim to identify an appropriate CBD formulation for oral administration. Due to its chemical composition, CBD is not well absorbed by the equine GI tract, with a bioavailability around 10%. According to previous research, the substance in which a drug is dissolved can have a large impact on systemic CBD levels, and the most effective candidates are usually composed of fats, such as sesame or canola oil. An optimized formulation is necessary to maximize therapeutic benefit while maintaining palatability for horses.
Phase Three
In phase three, researchers will combine the findings from the first two phases and analyze the effects of CBD on the drug-induced inflammatory response. A control group will receive no CBD, and researchers will evaluate the differences between the treated and untreated groups. Horses will be evaluated for several parameters, including the presence of biomarkers associated with inflammation within the joint and systemically throughout the body. They will quantify the mild lameness that is induced via an objective evaluation system that can better detect the subtleties of gait asymmetries when compared to the human eye.
Final Thoughts
Previous research has indicated that that CBD could be a promising option for managing chronic joint pain. This research should provide additional information on its efficacy in horses. The findings might be applicable to human medicine as well, given the mechanisms of OA and joint pain in humans often mimic those in horses. Since approximately 45% of people will develop some form of OA in their lifetimes, this potential is important. In the end, the researchers hope to provide a better research model for joint inflammation while simultaneously evaluating CBD as a way to manage joint pain in horses.
Related Reading
- Research Spotlight: Cannabidiol for Horses
- Therapeutic Effects of Intra-Articular Hyaluronic Acid With Gold Microparticles
- Injectable Gold: A Potential New Treatment for Equine Osteoarthritis?
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