Low back pain is a huge burden on our limited resources with limited knowledge of its pathophysiology. It is widely known that intervertebral disc degeneration (IDD) is intimately related, with the degree of degeneration associated with the severity of low back pain. The characteristics of intervertebral disc degeneration include disc height loss, proteoglycan loss, loss of water, annular fissures, and end plate calcification.
The degenerative process of the intervertebral disc has been seen as a phenotype change within the cells. This anabolic to catabolic shift seems to occur to the cells deep within the disc. One branch of research that studies the influence of mechanical forces on the biology is called Mechanobiology. In other words, can physical stressors on discs influence the process of degeneration? Can moving the disc is a certain way change the outcome of degeneration?
In this open access study, researchers were the first to investigate this kind of cyclical mechanical tension on the nucleus pulposus cell’s changing behaviour. They extracted disc cells from caudal spines of (3-month-old) male Sprague-Dawley rats and conducted the mechanical testing using a device after the cells were cultured and prepared. They used this device to apply mechanical force on the cells of the nucleus pulposus (the centre of the disc) to see how the cells behaved under specific loading conditions.
Disc cell senescence involves telomere shortening, free radical stress, DNA breakdown and cytokine proliferation. Mechanical loading conditions in the upright posture have been found to promote disc cell changes towards intervertebral disc degeneration in rats. Studying the role of mechanical stress and the influence on disc health will benefit our understanding of disc pathogenesis.
The results of this study showed a direct relationship of prolonged mechanical cyclic stress towards the catabolic shift of the cells in the nucleus pulposus. They concluded that unphysiological mechanical stress could push a disc into the degenerative cascade. They believe that eventually, too much mechanical stress can influence a cell’s behaviour and suggested that research continue searching the optimal mechanical environment for intervertebral disc cells.
At Dynamic Disc Designs, we work to bring dynamic models to the practitioner to help in the discussions related to motion and the spine.