Figure 5: Anabolic effects of CTGF, WISP2 and TGFβ1 in an in vitro model of DDD.

Effect of CTGF, WISP2 and TGFβ1 treatment alone or in combination on cell viability (72 hrs) as determined using MTT assays in NP cells obtained from (A) rat tail (healthy/injured) discs **p = 0.049, *p ≤ 0.02), (B) bovine degenerative disc NPs, *p < 0.01 and (C) human (H1, H2) degenerative disc NPs (*p < 0.005). Each bar represents mean ± S.D. of 3 independent experiments done in triplicates (n = 9). Cell proliferation assays (72 hrs) in (D) rat NP cells (healthy/injured discs), *p < 0.001, **p < 0.01 and (E) human (H1, H2) degenerative disc NPs treated with CTGF and TGFβ1 alone or in combination as determined using colorimetric anti-BrdU – ELISA, *p < 0.001. The p-values were determined using paired Student’s t-test, for treatment with CTGF, WISP2 or TGFβ1 alone or in combination with respect to no treatment control (NTC). (F) Histograms showing alterations in expression of collagen 2, HAPLN1, versican and thrombospondin1 (Thbs1) on treatment of human degenerative disc NP cells (H1, H2, H3) with CTGF and TGFβ1 as revealed by real time PCR analysis. Each bar in the histogram represents the mean ± S.D. of 3 independent experiments done in duplicates (n = 6, *p < 0.001).