Increased expression of interleukin-17 in degenerate human lumbar intervertebral discs tissues

[Objective]To investigate the expression of interleukin-17(IL-17) in degenerate human lumbar intervertebral discs tissues,and to explore the relationship between IL-17 expression and intervertebral disc degeneration. [Methods]IL-17 and retinoid-related orphan receptor(ROR)γτ mRNA levels were respectively measured by real-time quantitative reverse transcription-polymerase chain reaction(QT-PCR) in 42 surgical degenerative intervertebral discs tissues(26 samples from patients with lumbar disc herniation and 16 samples from patients with lumbar spinal stenosis) and 8 nondegenerated control tissue(from 4 autopsy).And the level of IL-17 protein,CD4 cell surface antigen was determined by immunohistochemistry EnVision method. [Results]The mean IL-17 and RORγτ mRNA levels in degenerate discs tissues group were significantly higher than that in autopsy controls(P0.05),but no significant differences were found between patients with LDH and spinal stenosis(t=0.669,P=0.507,t=421,P=0.380).The expression level of IL-17 mRNA was positively correlated with RORγτ(r=0.381,P0.001).Immunoreactivity of IL-17 and CD4 cell surface antigen were significantly greater in degenerate discs than in autopsy controls(P0.001),but no significant differences were found between patients with LDH and spinal stenosis(t=1.130,P=0.265,t=1.459,P=0.152). [Conclusion]The expression levels of IL-17 mRNA and IL-17 protein were significantly increased in degenerate human lumbar discs tissues than that in autopsy control tissues.These findings suggest involvement of IL-17 in the pathomechanism of intervertebral disc degeneration.Immune inflammation mediated by Th17 lymphocytes may play an important role in the development and progression of human lumbar intervertebral disc degeneration.