- 學位論文
探討硫化軟骨素、維生素C及維生素D對骨關節炎之防護機制
Study on the effects of chondroitin sulfate , vitamin C and vitamin D on osteoarthritis
摘要
骨關節炎（osteoarthritis，OA）為最常見的關節炎疾病，通常好發於中老年人，其疾病特徵主要為關節疼痛及關節軟骨磨損流失。隨著老年人口逐步提升，如何預防此疾病發生已逐漸受到重視，已有研究證實，硫化軟骨素能有效抑制發炎反應，降低關節腫脹及疼痛。有文獻指出血液中維生素C及維生素D含量較低者，其罹患骨關節炎的機率為正常人的三倍，顯示維生素C和維生素D可能有助於延緩骨關節炎之發生。然而，硫化軟骨素、維生素C及維生素D對於緩解骨關節炎之詳細調控機制仍尚未完全了解。因此本篇研究探討硫化軟骨素（chondroitin sulfate，CS）、維生素C（ascorbic acid，AA）及維生素D（1,25(OH)2D3）對於碘醋酸鈉（mono-iodoacetate，MIA）所誘發大鼠骨關節炎及人類軟骨細胞株SW-1353損傷後的保護影響。動物試驗（in vivo）結果顯示，大鼠關節腔內注射3 mg MIA導致軟骨組織降解及血漿中介白素-1β（interleukin-1β，IL-1β）、腫瘤壞死因子-α（tumor necrosis factor-α，TNF-α）及一氧化氮（nitric oxide，NO）的大量表現。然而當給予大鼠餵食4 mg / 500 μl 硫化軟骨素後，則有效降低發炎性細胞激素及一氧化氮的表現量，進而緩解軟骨損壞。細胞試驗（in vitro）中，以添加4 μM MIA刺激軟骨細胞損傷，再合併給予硫化軟骨素、維生素C及維生素D進行探討。其結果顯示相較於硫化軟骨素及維生素D，濃度100 μM 以上的維生素C 能有效保護MIA對軟骨細胞造成的直接損傷，其機轉為透過抑制TRAF6、MEK1、ERK1和JNK的表現，降低c-fos、c-jun和NF-κB轉錄活化，減少介白素-1β、基質金屬蛋白分解酶-1、-2、-3、-9之表現，以減緩軟骨細胞外基質流失達到保護軟骨細胞之功效。 綜合上述，硫化軟骨素藉由抑制MIA所誘發體內免疫發炎及NO產生來預防骨關節炎發生，但無法保護MIA直接誘導的軟骨細胞損傷；而維生素C則能直接保護軟骨細胞株SW-1353免於MIA的傷害，進而達到保護軟骨組織免於破壞之功效。顯示硫化軟骨素及維生素C較維生素D更具有保護軟骨組織之功效，故可延緩骨關節炎病程之惡化。
並列摘要
Osteoarthritis（OA）, a common form of joint disease and with joint pain as well as with a progressive loss of articular cartilage, affects more than half of the population over 65 years of age. Recently, it has obtained attention on how to prevent OA owing to the gradually increasing elderly population. Randomized clinical trials haves shown that chondroitin sulfate (CS) could diminish inflammatory effects and reduces joint swelling. In addition, studies have indicated those are of lower serum levels of vitamin C （L-ascorbic acid）and D （1,25(OH)2D3）have high prevalence of OA and that is three folds than normal. Based on theses findings, we proposed that CS, vitamin C and D might have chondroprotective effects. However, the exact mechanisms of their action on the progress of OA remain unclear. This study was designed to explore the effects of CS, vitamin C or vitamin D on the monoiodoacetate（MIA）-induced OA of rats and of human chondrosarcoma cell line SW-1353. In rats, intra-articular injection of 3 mg MIA caused transient cartilage proteoglycan degradation and significant increase of plasma levels of interleukin-1β（IL-1β）, tumor necrosis factor-α（TNF-α）and nitric oxide（NO）. Furthermore, oral administration of 4 mg CS could elicit anti-inflammatory effect with the decrease of cytokines and NO levels, meanwhile cartilage destruction was lessened. On the other hand, the addition of 4 μM MIA caused SW-1353 cell damaged. In addition, we found that vitamin C at the concentration of 100 μM was more protective against MIA-induced damage of SW-1353 than CS and vitamin D. Moreover, our results showed vitamin C was not only through the reduction in TRAF6, MEK1, ERK1 and JNK activation, but also c-fos, c-jun and NF-κB nuclear translocation resulting in inhibiting the expressions of IL-1β, MMP-1, -2, -3, -9. In summary, CS appears to elicit anti-inflammatory effects and to reduce NO production in the cartilage of MIA-treated keen joints; whereas it did not have effects on the MIA-induced damage in SW-1353 cells. Vitamin C can reduce the MIA-induced cell death of chondrocyte and improve cartilage change. These results suggest that CS and vitamin C are chondroprotective and lessen the destructive progression of OA.