Fig. 2

Biochemical analyses of pellets generated with healthy chondrocytes. a DNA and b sulfated glycosaminoglycan (GAG) content of chondrocyte pellets normalized to the DNA content (GAG/DNA). Data are expressed as fold-change in patients ≤55 years of age (left) or >55 years of age (right). All pellets were treated after the phase I culture (baseline) with the inflammatory treatment (IL-1β + TNF) and after 2, 7, and 14 additional days of culture in control (ctr) medium or notochordal cell conditioned medium (NCCM) (see Fig. 1 for experimental design). Data are means ± SD (n indicates the number of cartilage donors; for each donor two to three experimental replicates were analyzed); *p < 0.05 from baseline; °p < 0.05 from ctr (same recovery time). Treatment with NCCM does not result in any significant increase in DNA in either group of patients (a). In chondrocyte pellets from patients >55 years of age, NCCM treatment results in a significant increase in GAG/DNA content, returning to baseline levels at 14 days of culture; °p < 0.05 (b)