Figure 4.

Cytokine-associated gene expression in nucleus pulposus (NP) cells from non-degenerate, degenerate and infiltrated intervertebral discs (IVDs). Relative mRNA quantitation of cytokines and receptors was assessed by real-time q-PCR in cDNA samples from non-degenerate, degenerate and infiltrated study groups. Data shown are detection frequency (ν; pie charts) and relative expression per sample investigated (scatter plots). N-D, non-degenerate study group; D, degenerate study group; I, infiltrated study group; black star, significant difference in detection frequency between study groups (P <0.05); black diamond, significant difference in relative expression levels between study groups (P <0.05). LIFR, leukaemia inhibitory factor receptor.