Glucosamine sulfate for knee osteoarthritis: science and evidence-based use

Attenuation of IL-1ß on the use of glucosamine as an adjuvant in meloxicam treatment in rat models with osteoarthritis

Background Osteoarthritis (OA) is the most prevalent joint disease and a common cause of joint pain, functional loss, and disability. The severity of this disease is always associated with increased levels of proinflammatory cytokines, which play an important role in cartilage damage, synovitis, and other damage to joint tissues. The discovery that many soluble mediators such as cytokines or prostaglandins can increase the production of matrix metalloproteinases by chondrocytes led to the first steps of an inflammatory state. Several studies show that cytokines, such as interleukin 1ß, have a major role in the development of inflammation that occurs in these joints. The use of glucosamine as an adjuvant to meloxicam therapy is expected to inhibit the development of inflammatory OA. Methods The OA model in rat was induced by single injection of intraarticular monosodium iodoacetate (MIA). The development of OA was observed for 21 days. Furthermore, the evaluation of glucosamine potency as an adjuvant of meloxicam therapy for reducing IL-1ß was done by combined treatment at a low dose of meloxicam 1 mg/kg BW with glucosamine at a dose of 125, 250, or 500 mg/kg BW orally for 28 days. Response to hyperalgesia and knee joint diameter was measured on days 0, 7, 14, 21, 28, 35, 42, and 49. IL-1ß levels were measured on day 21 and day 49 after MIA injection. Results MIA injection successfully induced OA as marked by a significant difference in the time of latency to heat stimulus (p < 0.01) and a significant increase in joint diameter (p < 0.01). On day 21, IL-1ß levels showed a significant decrease in MIA injection (p = 0.05). The administration of meloxicam and glucosamine did not induce significant decrease in knee joint diameter (p > 0.10), but was able to significantly increase the latency time to heat stimulus (p < 0.01). IL-1ß levels also showed a significant decrease after administering a combination of glucosamine and meloxicam (p < 0.01). Conclusions Taken together, the use of glucosamine as an adjuvant in meloxicam therapy may be caused by the synergistic mechanism of meloxicam for the attenuation of OA development through systemically reducing IL-1ß.

Glucosamine dose/concentration-effect correlation in the rat with adjuvant arthritis

There is a debate on the dose dependency, concentration-effect, hence, the beneficial effect of glucosamine (GlcN), a widely used anti-inflammatory natural product. We investigated dose/concentration-effect relationship and determined its minimum effective dose/concentration in rats with adjuvant arthritis (AA, Mycobacterium butyricum in squalene) both as preventive and ameliorating interventions. To control already emerged arthritis, rats received oral doses of placebo or 160 mg/kg.day(-1) GlcN for 6 days. For prevention, rats were orally administered 0, 20, 40, 80, or 160 mg/kg.day(-1) GlcN commencing on the day of adjuvant injection. The arthritis index (AI), serum nitrite, and body weight were recorded. Subsequently, animals were cannulated in the right jugular veins and blood samples were collected for the determination of GlcN. GlcN ameliorated and, dose-dependently, prevented AA. It also controlled nitrite. AI was inversely correlated with GlcN dose, maximum plasma concentration, and the area under the concentration curve. Minimum effective dose was approximately 40 mg/kg.day(-1) that correspond to maximum plasma concentration of 1.37 ± 0.24 mg/L, close to 1.6 mg/L reported for pharmaceutical grades of GlcN to humans. GlcN efficacy is dose and concentration dependent. If the data extrapolated to humans, a higher than the commonly tested 1500 mg/kg dosage regimen may provide more clear treatment outcomes.