OBJECTIVETo evaluate the application of tendon-derived stem cells (TDSC) and bone marrow-derived mesenchymal stem cells (BMSC) for patellar tendon injury repair in rat model.

METHODSTDSCs and BMSCs were isolated from patellar tendons or bone marrow of healthy SD rats. The patellar tendon injury model was induced in 60 SD rats, then the animals were divided into 3 groups with 20 in each group: rats in TDSC group received transplantation of TDSC with fibrin glue in defected patellar tendon, rats in BMSC group received BMSC with fibrin glue for transplantation and those in control group received fibrin glue only. The gross morphology, histology and biomechanics of the patellar tendon were examined at 1, 2, 4, 6 and 8 weeks after the treatment.

RESULTSGross observation showed that the tendon defects in TDSC group and BMSC group almost disappeared in week 8, while the boundary of tendon defects in control group was still visible. Histology examination showed that the neo-tendon formation in TDSC group and BMSC group was observed at week 8, while there was no neo-tendon formation in control group. Biomechanics study showed that the ultimate stress and Young Modulus, relative ultimate stress and relative Young Modulus increased with the time going in all groups(all P<0.05); the ultimate stress and Young Modulus, relative ultimate stress and relative Young Modulus of TDSC and BMSC groups were significantly higher than those in control group at week 4, 6 and 8(all P<0.05). There was no difference in ultimate stress and Young Modulus between TDSC group and BMSC group(P>0.05), however, the relative Young Modulus of TDSC group was significantly higher than that in BMSC group at week 8(P<0.05).

CONCLUSIONAllogeneic TDSC and BMSC transplantation facilitates the repair of tendon injury and improves the biomechanics of tendon. TDSC is more suitable for in vivo tendon regeneration than BMSC.