Exogenous Glucosamine Globally Protects Chondrocytes from the Arthritogenic Effects of IL-1beta

Glucosamine proved to be a potent, broad-spectrum inhibitor of IL-1beta. Of the 2,813 genes whose transcription was altered by IL-1beta stimulation (p<0.0001), glucosamine significantly blocked the response in 2,055 (~73%). Glucosamine fully protected the chondrocytes from IL-1-induced expression of inflammatory cytokines, chemokines and growth factors as well as proteins involved in PGE2 and NO synthesis. It also blocked the IL-1-induced expression of matrix specific proteases such as MMPs -3,-9,-10,-12 and ADAMTS-1. Keywords: treatment response Articular cartilage was isolated from the femoral heads of male Wistar rats under aseptic conditions. Chondrocytes were obtained by sequential digestion of the cartilage with pronase and type II collagenase. After filtration to remove tissue debris, the cells were cultured in 75-cm2 flasks in complete Dulbecco’s Modified Eagle Medium (DMEM; supplemented with 10% fetal bovine serum and 1% penicillin-streptomycin at 37°C in a humidified atmosphere containing 5% CO2. Experiments were subsequently performed with second-passage cultures whereby the cells from the large cultures were trypsinized, pooled and seeded into twenty 25 cm2 flasks. These were then divided into 4 treatment groups to evaluate the effects of glucosamine and IL-1 on global transcription patterns.To the culture medium in half of the flasks, glucosamine, HCl was added to a final concentration of 20 mM. Six hours later, IL-1beta was added at 10 ng/ml to 5 of the flasks receiving glucosamine and to 5 of the untreated flasks. Fourteen hours post IL-1beta stimulation, total RNA was isolated individually from the respective cultures and microarray experiments processed.