Increased Expression of Inflammatory Cytokines in Diseased Cervical Intervertebral Disc is Associated with Discogenic Neck Pain

Abstract

Abstract Background: Chronic neck pain is frequently encountered in clinical practice, but its etiology is still poorly understood. The degenerative cervical intervertebral disc is the main cause of chronic neck pain reported, accounting for about 16%-41% of all incidents. Inflammation is associated with intervertebral disc degeneration and the occurrence of discogenic low back pain; however, whether inflammation plays a key role in the pathogenesis of discogenic neck pain has not been reported in the literature. The aim of the present study was to explore the relationship between inflammatory cytokines and discogenic neck pain and to elucidate the possible pathogenesis of discogenic neck pain. Methods: A total of 111 intervertebral disc samples were collected during the present study: 38 samples from the discogenic neck pain group, 41 samples from the symptomatic control group, and 32 samples from the normal control group. The concentration in each sample of NO, IL-1, IL-6 and TNF- α was determined using ELISA and then statistically analyzed as to whether there were significant differences among the three groups. Results: The expression of inflammatory cytokines in disc samples from patients with severe neck pain was increased in comparison with the disc samples from patients without or with only mild neck pain and fresh cadavers. The differences are statistically significant（P＜0.001). However, the difference of the degree of disc degeneration was not statistically significant between the discogenic neck pain group and symptomatic control group（P＞0.05). Conclusions: The increased expression of inflammatory cytokines in diseased cervical intervertetral discs may play a key role in the pathogenesis of discogenic neck pain. Although inflammation is involved in intervertebral disc degeneration, there is no linear positive correlation between the concentration of inflammatory cytokines and the degree of disc degeneration.