Takahashi Daisuke, Iwasaki Norimasa, Kon Shigeyuki, Matsui Yuichiro, Majima Tokifumi, Minami Akio, Uede Toshimitsu
Department of Orthopaedic Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
Arthritis Rheum. 2009 Aug;60(8):2372-80. doi: 10.1002/art.24718.
The hypothesis of this study was that synovial factors playing a pivotal role in the pathogenesis of osteoarthritis (OA) and thus gene expression in the synovium would be altered at the initial stage of OA. The aims of this study were to identify the candidate genes in synovium related to OA initiation, to evaluate cartilage degeneration after knockdown of the gene using small interfering RNA (siRNA) gene silencing in the knee joints at the initial stage of OA, and to determine the potential role of the knocked-down gene in OA initiation.
Genes overexpressed in synovium at the initial stage of disease in a rabbit model of anterior cruciate ligament transection (ACLT)-induced OA were identified using the suppression subtractive hybridization technique and differential screening. Candidate gene expression in the synovium of the knees of rabbits with OA was manipulated with electroporation-assisted siRNA transduction 4 times before and after operation. Four weeks after surgery, histologic analysis was performed.
Cathepsin K gene and protein expression was significantly up-regulated in synovium at the initial stage of OA in rabbits. Down-regulation of cathepsin K in synovium at the initial stage of OA significantly accelerated cartilage degeneration.
These results indicate that cathepsin K plays a protective role in cartilage degeneration at the initial stage of OA. We believe that the current results obtained from models of the early phase of OA will provide useful information for developing a novel strategy to prevent disease progression.
本研究的假设是滑膜因子在骨关节炎（OA）发病机制中起关键作用，因此OA早期滑膜中的基因表达会发生改变。本研究的目的是鉴定滑膜中与OA起始相关的候选基因，在OA早期通过小干扰RNA（siRNA）基因沉默技术敲低该基因后评估膝关节软骨退变情况，并确定被敲低基因在OA起始中的潜在作用。
利用抑制性消减杂交技术和差异筛选，鉴定在兔前交叉韧带横断（ACLT）诱导的OA模型疾病早期滑膜中过表达的基因。在手术前后用电穿孔辅助的siRNA转导对OA兔膝关节滑膜中的候选基因表达进行4次调控。术后4周进行组织学分析。
在兔OA早期滑膜中，组织蛋白酶K基因和蛋白表达显著上调。在OA早期滑膜中下调组织蛋白酶K可显著加速软骨退变。
这些结果表明组织蛋白酶K在OA早期软骨退变中起保护作用。我们认为，目前从OA早期模型获得的结果将为制定预防疾病进展的新策略提供有用信息。
