Mechanisms and kinetics of glycosaminoglycan release following in vitro cartilage injury
Mechanisms and kinetics of glycosaminoglycan release following in vitro cartilage injury
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DOI：
10.1002/art.20101
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发表时间：
2004-03-01
影响因子：
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通讯作者：
Grodzinsky, AJ
中科院分区：
文献类型：
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作者：
DiMicco, MA;Patwari, P;Grodzinsky, AJ
Objective.急性关节损伤导致骨关节炎（OA）风险增加。虽然这种进展的机制尚不清楚，但OA的早期结构、代谢和成分指标已使用软骨损伤的体外模型重现。本研究旨在确定体外软骨损伤后糖胺聚糖（GAG）的损失是否由细胞生物合成、酶活性激活或软骨细胞外基质的机械破坏介导。将未成熟的牛软骨培养长达10天。3天后，对各组样品进行有害的机械压缩（单轴无侧限压缩至50%厚度，应变速率100%每秒）。测量释放到培养基中的GAG，并将其水平与位置匹配的未受伤对照组进行比较。在培养液中添加生物合成抑制剂（放线菌酮）、基质金属蛋白酶（NIMP）活性抑制剂（CGS 27023 A或GM 6001）和聚集蛋白聚糖酶活性抑制剂（SB 703704）对损伤后GAG释放的影响。损伤软骨的GAG释放在损伤后的前4小时内最高，但在损伤后的前24小时内仍高于对照组，并且不受生物合成或降解酶抑制剂的影响。损伤后24-72小时的GAG释放与未损伤对照组相似，但MMP抑制剂CGS 27023 A减少了损伤后1天至7天损伤样品的累积GAG损失。其他酶降解或生物合成抑制剂对GAG释放无显著影响。关节软骨的损伤性压迫诱导最初高速率的GAG从组织释放，这不能被抑制，与机械损伤一致。然而，MMP抑制减少损伤后几天内GAG损失的发现表明了潜在的治疗干预。
Objective. Acute joint injury leads to increased risk for osteoarthritis (OA). Although the mechanisms underlying this progression are unclear, early structural, metabolic, and compositional indicators of OA have been reproduced using in vitro models of cartilage injury. This study was undertaken to determine whether glycosaminoglycan (GAG) loss following in vitro cartilage injury is mediated by cellular biosynthesis, activation of enzymatic activity, or mechanical disruption of the cartilage extracellular matrix.Methods. Immature bovine cartilage was cultured for up to 10 days. After 3 days, groups of samples were subjected to injurious mechanical compression (single uniaxial unconfined compression to 50% thickness, strain rate 100% per second). GAG release to the medium was measured, and levels were compared with those in location-matched, uninjured controls. The effects of medium supplementation with inhibitors of biosynthesis (cycloheximide), of matrix metalloproteinase (NIMP) activity (CGS 27023A or GM 6001), and of aggrecanase activity (SB 703704) on GAG release after injury were assessed.Results. GAG release from injured cartilage was highest during the first 4 hours after injury, but remained higher than that in controls during the first 24 hours postinjury, and was not affected by inhibitors of biosynthesis or degradative enzymes. GAG release during the period 24-72 hours postinjury was similar to that in uninjured controls, but the MMP inhibitor CGS 27023A reduced cumulative GAG loss from injured samples between 1 day and 7 days postinjury. Other inhibitors of enzymatic degradation or biosynthesis had no significant effect on GAG release.Conclusion. Injurious compression of articular cartilage induces an initially high rate of GAG release from the tissue, which could not be inhibited, consistent with mechanical damage. However, the finding that MMP inhibition reduced GAG loss in the days following injury suggests a potential therapeutic intervention.