Evaluation of inflammatory responses induced via intra-articular injection of interleukin-1 in horses receiving a dietary nutraceutical and assessment of the clinical effects of long-term nutraceutical administration

Abstract

To evaluate inflammatory responses induced via intra-articular recombinant human interleukin (IL)-1beta treatment in horses receiving a dietary nutraceutical (DN; composed of mussel, shark cartilage, abalone, and Biota orientalis lipid extract) and assess the clinical effects of long-term DN administration. 22 healthy horses. 12 horses were fed 0, 15, 45, or 75 mg of DN (3 horses/treatment) daily for 84 days. General health and clinicopathologic variables were monitored at intervals. Ten other horses received 0 or 15 g of DN/d (5 horses/treatment) for 29 days (beginning day -14). One intercarpal joint in each horse was injected twice with IL-1beta (10 and 100 ng on days 0 and 1, respectively), and the contralateral joint was similarly injected with saline (0.9% NaCl) solution. Synovial fluid prostaglandin E(2) (PGE(2)), sulfated glycosaminoglycan (GAG), nitric oxide (NO), and protein concentrations and leukocyte counts were analyzed before and at intervals after injections. Administration of the DN (up to 75 g/d) to horses for 84 days did not induce any adverse effects. In the other experiment, synovial fluid PGE(2), GAG, and protein concentrations and leukocyte count increased after intra-articular injections of IL-1beta (compared with effects of saline solution injections) in horses that received no DN; NO concentration was not affected. In horses that were fed the DN, intra-articular IL-1beta injections did not induce significant increases in synovial fluid PGE(2) and GAG concentrations. Results suggested that administration of the DN may be useful in preventing inflammation associated with arthritis and degenerative joint disease in horses.