Chondroprotective effect of N-acetylglucosamine and hyaluronate in early stages of osteoarthritis--an experimental study in rabbits.

Osteoarthritis, the most common joint disease in the world, is characterized by joint pain, stiffness, and limitation of range of motion. Osteoarthritis is a slowly progressive disease and its morbidity increases with age. The most commonly involved sites are the spine, knee, hip, and hand joints. Although the ideal treatment for osteoarthritis should be the one that acts on the underlying mechanism, thus preventing joint destruction and disease progression, such an effective treatment option does not exist. Therefore, contemporary treatment aims to relieve pain, increase range of motion, and optimize joint function. Analgesics and nonsteroidal antiinflammatory drugs are most commonly used for the symptomatic treatment, but mainly their gastrointestinal side effects, especially in elderly patients, limit their usage. In this study, the chondroprotective effects of an aminomonosaccharide glucosamine and a polysaccharide hyaluronic acid in a rabbit osteoarthritis model were investigated. Anterior cruciate ligament transection was performed in 32 New Zealand rabbits to establish a model of osteoarthritis. Rabbits were randomized into four groups, each consisting of eight rabbits. Two weeks after the operation, intraarticular injections were performed to the right knees once a week for 5 weeks; intraarticular glucosamine to the first group, intraarticular hyaluronate to the second group, intraarticular hyaluronate and intramuscular glucosamine to the third group, and intraarticular saline solution to the fourth group, which served as the control group. At the end of the eighth week, the rabbits were sacrificed and their right knees with proximal femur and distal tibia were harvested. Joint surfaces of their femur and tibia were examined macroscopically, and sections from the medial femoral condyles were examined microscopically. Macroscopic evaluation revealed that the cartilage surface was preserved in the glucosamine, hyaluronate, and hyaluronate plus glucosamine groups, when compared with the control group. Microscopic evaluation showed that glucosamine, hyaluronate, and glucosamine plus hyaluronate have chondroprotective effect, but no statistically significant difference was found between study groups.