Glucosamine and Chondroitin
Monitoring equine joint disease and determining the effects of nutraceutical agents, such as chondroitin sulfate (CS) and glucosamine (GlcN), is difficult to say the least. However, a group of Brazilian researchers recently determined that analyzing urinary glycosaminoglycans (GAGs) could be helpful, especially in mild osteoarthritis (OA) cases.

Raquel Baccarin, DVM, PhD, professor of veterinary medicine at University of Sao Paulo, recently led a two-part study analyzing the urinary excretion of GAGs (polysaccharides abundant in joint cartilage) in both healthy and OA-affected athletic Warmblood horses and evaluating the effects of CS and GlcN on mild equine OA.

“Since glucosamine is a precursor for GAGs … supplemental glucosamine or chondroitin sulfate may help to prevent cartilage degeneration and treat OA,” Baccarin explained.

Researchers analyzed urinary GAGs in 20 healthy horses and 27 horses diagnosed with mild OA. The team found that OA-affected horses excreted more urinary GAGs than their healthy counterparts.

Subsequently, six of the OA-affected horses received two treatment protocols, administered two months apart:

  • 10 mL of intramuscular CS + GlcN given every five days for 25 days; and
  • 800 mg of oral GlcN every day for 25 days.

Researchers systemically collected urine samples during and after each treatment protocol, up to Day 184 post-treatment. They found that GAGs, especially CS, appeared and remained at high levels in the urine for about three months after the end of treatment, indicating the compound was well-distributed in the body.

“This finding suggests even higher turnover of cartilage rates, perhaps in an attempt of the cartilage to regenerate itself,” reported Baccarin.

Each horse underwent a physical examination, which included joint palpation and manipulation, lameness grading, joint flexion tests, and radiographic evaluation, before and 60 days after starting each treatment protocol. After CS+GlcN treatments, the researchers’ assessments revealed significant improvement in flexion tests, slight decrease in joint volume and lameness scores, and slight improvement in radiographic scores.

The team concluded that urinary GAGs are reliable indicators of cartilage turnover rates and can be useful in monitoring joint disease. They also found that supplemental CS and GlcN had beneficial effects on mild OA in horses.

“These results suggest that treatment protocol proposed for mild osteoarthritis has a longer than expected effect, and that supplementation with chondroitin sulphate and glucosamine sulphate can be prescribed in an interrupted pattern throughout the desired treatment period, alternating three months of supplementation with three months without,” Baccarin said. “Research is still being conducted to determine quality of tissue repair in supplemented animals to further justify supplementation.”

The study, “Urinary glycosaminoglycans in horse osteoarthritis. Effects of chondroitin sulfate and glucosamine,” recently appeared in Research in Veterinary Science. The article is available online.