mRNA expression of NOTCH2 and inflammatory cytokines IL-1β and TNF-α in 49 human disc samples.
A, NOTCH2 mRNA expression was highest in mid-grade degenerate discs (grades 4–6), which was significant compared with non-degenerate discs (p = 0.04). B, NOTCH1 mRNA expression was highest in mid-grade degenerate discs (grades 4–6), although this failed to reach significance (p = 0.19). C, HEY2 mRNA expression was highest in mid-grade degenerate discs (grades 4–6), although this failed to reach significance (p = 0.35). D, a positive (+ve) correlation in mRNA levels between NOTCH1 and NOTCH2 was observed (p < 0.0001). v/s: versus. E, a positive correlation in mRNA levels between NOTCH 1 and HEY2 was observed (p = 0.0012). F, a positive correlation in mRNA levels between NOTCH2 and HEY2 was noted (p = 0.034). G, IL-1β mRNA expression was significantly increased in mid-grade degenerate discs compared with non-degenerate discs (p = 0.018). H, TNF-α mRNA expression was increased in mid-grade degenerate discs, although this failed to reach significance (p = 0.38).