Comparison of growth factor and cytokine expression in patients with degenerated disc disease and herniated nucleus pulposus

ObjectivesThis study was conducted to investigate the expression of cytokines and growth factors in disc specimens obtained from patients with herniated nucleus pulposus (HNP) and degenerated disc disease (DDD).Design and methodsMRI and Western blot analyses were performed to evaluate the levels of disc degeneration and the expression levels of cytokines and growth factors.ResultsThe levels of TNF-α and IL-8 were significantly greater in the DDD group than in the HNP group, but no statistical differences were observed in the expression of IL-1β, IL-6 and IL-12 between the HNP and DDD groups. In addition, the expression of TGF β, VEGF and NGF was significantly higher in the DDD group than in the HNP group.ConclusionThe greater levels of cytokine and growth factor expression in the DDD group than in the HNP explain why discogenic patients usually have more severe back pain than patients with herniated discs.