Boxplot graph of cell viability.

The graph shows cell viability (mean percentage live cells ± SD) at baseline (day 0; gray boxplots) and after the 14 day culture period with respectively SPL load (red), high dynamic load (green) and high static load (blue). The cell viability data is split on the x-axis over the five distinct IVD regions; nucleus (NP), inner annulus (iAF), and the outer annulus (oAF, anterior; lateral and posterior). Brackets indicate significant statistical differences between groups when comparing in a linear mixed model with Bonferroni post-hoc testing: P values are indicated by: ^ap<0.05; ^bp<0.01; ^cp<0.001.