Neosaxitoxin, a Paralytic Shellfish Poison phycotoxin, blocks pain and inflammation in equine osteoarthritis.

The Osteoarthritis is a chronic disease characterized by a progressive deterioration of the articular cartilage producing a strong inflammatory activity and chronic pain in patients. Horses also show osteoarthritis. Since the activation and progression of the disease are similar to that of human we developed a study model in horses. In this study, we test the effect of Neosaxitoxin, a phycotoxin from Paralytic Shellfish Poison, in the remediation of osteoarthritis equine clinical symptoms such as pain (showed in lameness) and inflammation quantifying the amounts of pro-inflammatory markers like cellular infiltration, TNF-alpha and nitric oxide in the synovial fluid obtained from the horse damaged joint. The outcomes show that Neosaxitoxin blocks pain for long lasting period (average 24.7 days). Furthermore, the amounts of pro-inflammatory markers were reduced and consequently an enhanced horse's well-being was obtained. Neosaxitoxin showed to be a candidate for establishing treatment protocols for OA, being safe and effective as a pain blocker in equine osteoarthritis.