Fig. 4.

Verification of the expression of candidate genes in normal (IVD) and degenerated (IDD) NP primary cells. a The expression of TNFAIP6, CHI3L1, KRT19, DPT, COL6A2, and COL11A2 were examined in normal (IVD, n = 6) and degenerated (IDD, n = 6) NP tissues using immunohistochemistry. b The quantifications of the immunohistochemistry analysis were performed to show the relative expression level of the candidate genes. c The RNA expression level of these candidate genes in normal (IVD, n = 3) and degenerated (IDD, n = 3) NP primary cells were assessed using real-time PCR method. d The RNA expression level of these candidate genes in normal (NC, n = 3) and IL-1β (50 ng/ml, resembles the degeneration process in vitro, n = 3) treated NP primary cells were assessed using real-time PCR method. RNA level of GAPDH was used as internal reference. All Data are represented as mean ± SD, **p < 0.01