Figure 1. Effects of circulatory factors on aggrecan mRNA and protein expression in intervertebral discs in mouse heterochronic parabionts. (A) representative aggrecan immunofluorescent (red) images of nucleus pulposus (NP) tissue of the parabionts. Quantification of the NP aggrecan immunofluorescence is shown in the bar graph. (B) Disc aggrecan mRNA levels were quantified by qRT-PCR and normalized to GAPDH. Data shown are mean ± SEM of five independent experiments (n=5 per group), *p < 0.05. Scale bar = 20 μm.