- 學位論文
葡萄糖胺在軟骨細胞上抑制間質分解酵素-3之機制
The inhibitory of glucosamine on the MMP-3 expression in chondrocyte
摘要
退化性關節炎，是由於關節軟骨內的軟骨細胞合成及降解作用功能失去平衡所引起。而間質分解酵素（matrix metalloproteinase）能降解細胞外間質，故MMP 在退化性關節炎病理中扮演重要角色。介白質-1（Interlukin-1）是一種趨化激素，存在於退化性關節炎軟骨及滑液膜中。IL-1beta參予基質（matrix）降解及減少醣蛋（proteoglycan） 合成。IL-1 藉著調控一氧化氮合成?（nitric oxide synthase）及MMP的活化來參予此代謝過程。葡萄醣胺（glucosamine）可能會刺激醣蛋白合成、抑制醣蛋白降解作用並且在體內刺激軟骨中的醣蛋白再生。在我們加入glucosamine 發現，glucosamine 會調控MMP-3 表現。為了進一步確認glucosamine 抑制MMP-3 的知訊息傳遞路徑，我們使 用glucosamine 抑制蛋白激?是否有被磷酸化。在我們結果發現，glucosamine 可誘導Akt、ERK 及JNK 的活化。而glucosamine 會使得p38 磷酸化及NF-kB 表現受到抑制。在Akt 抑制劑部分，當加入wortmannin，會抑制glucosamine 所誘導Akt 的磷酸化，而不會影響ERK 的磷酸化。根據以上結果推論，glucosamine 經由活化Akt調控軟骨細胞，進而抑制IL-1所誘導NF-kB的路徑。
並列摘要
Osteoarthritis（OA） is characterized by loss of the functional intergrity of articular cartilage due to an imbalance between catabolic and anabolic chondrocyte activity. Degradation of the collagenous extracellular matrix by metalloproteases（MMPs）play an important role in the pathogenesis of osteoarthritis. Interleukin-1 (IL-1), a cytokine present which in elevated in OA cartilage and synovial fluid.IL-1?is an important mediator of increase matrix degradation and reduced PG synthesis. IL-1 mediates this process by a number of metabolic processes including up-regulating enzymes such as nitric oxide synthase, matrix metalloproteinase. Glucosamine is capable of stimulating PG synthesis, inhibiting the degradation of PGs, and stimulating the regeneration of cartilage in vivo. It showed that the expression of metalloproteases-3（MMP-3）was downregulated by treatment of glucosamine. To examine which signal pathway are involved in the MMP-3 expression by glucosamine, several kinase pathway are investigated the phosphorylation status. The result showed that glucosamine activated Akt, ERK and JNK pathway. Beside, glucosamine inhibited p38 phosphoylation and NF-kB translocated to nucleus. The Akt inhibitors, wortmannin, blocked glucosamine stimulated Akt phosphorylation without blocking ERK phosphorylation. These results provide evidence of glucosamine inhibit IL-1?induced NF-kB pathway via Akt phosphorylation regulation in chondrocyte.