LMP-1 Suppresses Intervertebral Disc Degeneration by Inhibiting MMPs Expression

Introduction LIM mineralization protein-1(LMP-1) is an intracellular regulatory molecule in bone formation. Previous studies have proved that it has beneficial effects on intervertebral disc regeneration in vitro and in vivo. However the mechanism of LMP-1 suppresses intervertebral disc degeneration remains unknown. The purpose of the present study was to identify the protective role of LMP-1 in a TNF-α induced intervertebral disc degeneration cell model. Materials and Methods TNF-α induced extracellular matrix degradation of rat nucleus pulposus cells (NPCs) was used to imitate intervertebral disc degeneration. Cultured NPCs were transfected with rLMP-1 siRNA to knock down the LMP-1 expression, sulfated glycosaminoglycan (sGAG) dyeing, real-time polymerase chain reaction (RT-PCR), and western blotting were used to analyze proteoglycan, mRNA, and protein levels, respectively. Two days later, the mRNA levels of MMPs were measured. Results In vitro experiments revealed that the sulfated glycosaminoglycan (sGAG) level was significantly reduced with the rLMP-1 siRNA treatment, while the mRNA level of MMP3 and MMP13 increased. TNF-α down-regulated the proteoglycan expression in NPCs, knocking down LMP-1 expression had significantly elevated levels of MMP3 and MMP13 mRNA, accompanied with the decrease of sGAG level. Conclusion LMP-1 suppresses TNF-α induced intervertebral disc degeneration by inhibiting MMPs expression. Disclosure of Interest None declared