This study is to investigate the role of digoxin in the pathogenesis of intervertebral disc degeneration as well as the involved molecular mechanism, particularly the potential target protein.
We exploited a rat needle model to investigate digoxin\'s role in intervertebral disc degeneration in vivo. Safranin O staining was used to measure cartilaginous tissue in the intervertebral disc. The morphological changes of intervertebral discs in animal models were determined by Hematoxylin-Eosin (H&E) staining and the pathological score. Primary nucleus pulposus cells (NP cells) from intervertebral discs of patients and murine were used in the present study. Western-Blotting assay, Real-time PCR assay, immunofluorescence staining, and immunochemistry were used to detect the role of digoxin in anti-TNF-α-induced inflammatory effects in vitro. Transfection of siRNA was used to regulate low-density lipoprotein receptor-related protein 4 (LRP4) expression in NP cells to investigate the potential protein target of digoxin.
Digoxin protected against intervertebral disc degeneration in rat needle models. Digoxin was found to exert its disc-protective effects through at least three different pathways by a) suppressing TNF-α-induced inflammation, b) attenuating ECM destruction, c) significantly promoting ECM anabolism. Additionally, LRP4 was found to be the downstream molecule of digoxin in NP cells for anti-inflammation and regulation of ECM metabolism. The knockdown of LRP4 downregulated the protective effect of digoxin in NP cells.
These findings suggest that digoxin may be a potential therapeutic agent for intervertebral disc degeneration through anti-catabolism and pro-anabolism. Digoxin might also work as an alternative for other inflammation-related diseases.
■本研究旨在探讨地高辛在椎间盘退变发病中的作用及其分子机制。特别是潜在的靶蛋白。
■我们利用大鼠针头模型来研究地高辛在体内椎间盘退变中的作用。SafraninO染色用于测量椎间盘中的软骨组织。通过苏木精-伊红(H&E)染色和病理评分确定动物模型中椎间盘的形态学变化。本研究使用来自患者和小鼠椎间盘的原代髓核细胞(NP细胞)。蛋白质印迹分析,实时PCR检测,免疫荧光染色,和免疫化学方法检测地高辛在体外抗TNF-α诱导的炎症作用中的作用。转染siRNA调节NP细胞低密度脂蛋白受体相关蛋白4(LRP4)的表达,探讨地高辛潜在的蛋白靶点。
■地高辛在大鼠针刺模型中保护椎间盘退变。发现地高辛通过至少三种不同的途径发挥其椎间盘保护作用,其途径是a)抑制TNF-α诱导的炎症,b)衰减ECM破坏,c)显著促进ECM合成代谢。此外,发现LRP4是NP细胞中地高辛的下游分子,用于抗炎和调节ECM代谢。LRP4敲低下调地高辛对NP细胞的保护作用。
■这些研究结果表明,地高辛可能通过抗分解代谢和促合成代谢成为治疗椎间盘退变的潜在药物。地高辛也可能作为其他炎症相关疾病的替代品。