Abstract:

BACKGROUND: Several studies have confirmed that activation of intervertebral disc enzymes is closely related to matrix degradation. Matrix metalloproteinase and tissue inhibitor of metalloproteinase have been shown to exert important roles in the process of extracellular matrix degeneration in intervertebral disk. Besides these two enzyme systems, whether other proteases that exhibit degrading effects on extracellular matrix are involved in the intervertebral disk degeneration remains poorly understood. 
OBJECTIVE: To detect the cathepsin K expression in normal and degenerated human intervertebral disc cells and investigate the correlation between cathepsin K and intervertebral disc degeneration.
METHODS: Cathepsin K expression was detected in intervertebral disc tissue from 30 patients with lumbar intervertebral disc protrusion using immunohistochemistry SP method and ELISA. At the same time, the intervertebral disc tissue from 15 healthy adult cadavers and/or spine fracture patients was taken as control. Cathepsin K protein expression in normal and degenerated human intervertebral disc tissues were compared.
RESULTS AND CONCLUSION: Cathepsin K expression was observed in normal and degenerated intervertebral disc tissues. The expression level was significantly higher in degenerated tissue than normal tissue (P < 0.05). These findings demonstrate that Cathepsin K possibly participates in the intervertebral disc degeneration.