Comparative study of normal and osteoarthritic canine synovial fluid using500 MHz H-1 magnetic resonance spectroscopy

High resolution H-1 nuclear magnetic resonance spectroscopy has been used t o investigate and compare the metabolic profiles of normal and osteoarthrit ic synovial fluids in a canine model of osteoarthritis. The spectra of oste oarthritic synovial fluid showed (a) increased concentrations of lactate, p yruvate, lipoprotein-associated fatty acids, and glycerol as well as the ke tones hydroxybutyrate and hydroxyisobutyrate, (b) reduced levels of glucose , and (c) elevated levels of N-acetylglycoproteins, acetate, and acetamide compared with healthy normal canine synovial fluid. An increase was also ob served in the concentrations of the amino acids alanine and isoleucine. The se results suggest that (a) the intraarticular environment in canine osteoa rthritis is more hypoxic and acidotic than in a normal joint, (b) lipolysis may play an increasingly important role as a source of energy in osteoarth ritis, and (c) the N-acetylglycoprotein polymer component of synovial fluid (mostly hyaluronan) seems to be increasingly fragmented and degraded into acetate by way of an acetamide intermediate with progressive osteoarthritis . The observed changes in the biochemical profile of canine osteoarthritic synovial fluid may be useful in understanding alterations in joint metaboli sm consequent to arthritic diseases and helpful in identifying potential ma rkers of osteoarthritis.