Figure 1: Effect of age on stem/progenitor cell numbers in rat Achilles, patellar and tail tendons. Primary tendon derived cells from 3 and 12 month old rats were obtained by collagenase digestion and cultured in the CFU-f assay. Mean colony number (A), mean colony size (B) and colonies/mg tissue (C) were determined. * indicates a significant difference (p < 0.05) compared to the corresponding tendons from younger animals. Data are presented as mean ± SEM.