Comparative Study of the Ability of Tendon Stem Cells and Bone-Marrow Stem Cells to Promote the Repair of the Tendon-Bone Interface

The aim of this study was to compare the capacity of tendon stem cells (TSCs) and bone-marrow stem cells (BMSCs) to promote tendon-bone repair to screen for seed cells that better promote tendon-bone healing. The properties of these two types of cells that were relevant for the repair of the tendon-bone interface were compared in vitro. The results revealed that TSCs tended to have a higher proliferative ability (based on CCK-8 assays) and higher expression levels of a tenogenic marker, Scx (based on qRT-PCR), whereas BMSCs tended to have higher expression levels of osteogenesis-related genes (AlpL and Runx2), but the expression level of the chondrogenic marker Sox9 were the same in TSCs and BMSCs, as shown using qRT-PCR analysis. We transplanted these stem cells into the tendon-bone junction of rats. At 8 week post-surgery, specimens exhibited some heterotopic ossification, with lower levels observed in the TSC group than in the other groups, although the difference was not significant. Alcian-blue staining showed that at 4 weeks post-surgery, more fibrocartilaginous structures had formed in the TSC group than in the BMSC or control groups (p < 0.05). There was no significant difference between the TSC group and the BMSC group at 8 weeks post-surgery. Picrosirius-red staining showed that the collagen of the repaired tendon bone junction in the TSC group was more organized than that in the other groups. Taken together, these results strongly suggested that TSCs are potential seed cells for tissue engineering to promote tendon-bone healing and that TSCs have a greater ability to promote tendon-bone interfacial repair than do BMSCs.