Topic Overview:
Intervertebral disc degeneration is ubiquitous among older patients and is commonly associated with low back pain. The individual and societal costs of low back pain are enormous, and current treatment options are sub-optimal. Although motion-based therapies continue to increase as treatment options for low back pain, rational design of exercise-based therapies is limited by a lack of understanding of the molecular effects of mechanical loading in the intervertebral disc. Dr. Sowa’s laboratory investigates the response of the intervertebral disc to mechanical forces. Her laboratory has established metabolically active tension and compression systems capable of examining mechanical signaling pathways in intervertebral disc cells. In addition, used in conjunction with established animal models of disc degeneration, the systems can examine responses of normal and degenerative cells to mechanical loading as well as identify matrix breakdown products peripherally in vivo.

Initial studies demonstrated a profound anti-catabolic effect of mechanical stimulation, decreasing gene expression of key mediators of matrix catabolism. Follow up experiments to examine magnitude and frequency dependence demonstrated that a threshold exists, beyond which the mechanical stimulation may initiate a catabolic response. In addition, it has become increasing clear that the NFκB signaling pathway is involved in these responses. Comparisons made between normal and degenerative cells demonstrate differences in their response to mechanical loading. This finding provides insight into why patients with differing levels of disease may respond differently to exercise-based regimens.