Figure 1

Study outline and experimental approaches. Initial low density array (LDA) analysis of cells isolated from human nucleus pulposus (NP) tissue samples identified a diverse cytokine and chemokine expression profile. From these data, 30 targets were selected for further gene expression analysis by real-time qPCR and 4 targets were selected for protein production and localisation analysis by immunohistochemistry. Consideration was given to the frequency at which targets were detected and any differential expression profile observed between non-degenerate and degenerate study groups to select targets for further investigation. Consideration was also given to the detection of receptor mRNA expression (indicating potential for autocrine or paracrine signalling involvement), whether the roles of identified targets had previously been well studied, the identification of novel targets within the intervertebral disc, and links to cytokine and chemokine activity in other arthropathies.