The Effects of Platelet-Rich Plasma on Bone Marrow Stromal Cell Transplants for Tendon Healing In Vitro

Purpose: In this study, we investigated the effect of platelet-rich plasma (PRP) and bone marrow-derived stromal cell (BMSC)-seeded interposition in an in vitro canine tendon repair model.

Methods: Bone marrow, peripheral blood, and tendons were harvested from mixed-breed dogs. Bone marrow-derived stromal cells were cultured and passaged from adherent cells of bone marrow suspension. Platelet-rich plasma was purified from peripheral blood using a commercial kit. A total of 192 flexor digitorum profundus tendons were used for the study. Tendons repaired with a simple suture were used as a control group. In treatment groups, a collagen gel patch was interposed at the tendon repair site before suture. There were 3 treatment groups, according to the type of collagen patch: a patch with PRP, a patch with BMSC, and a patch with PRP and BMSC. The repaired tendons were evaluated by biomechanical testing and by histological survey after 2 and 4 weeks in tissue culture. To evaluate viability, cells were labeled with PKH26 red fluorescent cell linker (Sigma, St. Louis, MO) and surveyed under confocal microscopy after culture.

Results: The maximum breaking strength and stiffness of the healing tendons with the BMSC-seeded PRP patch were significantly higher than those of the healing tendons without a patch or with a cell-seeded patch (p < .02). Viable BMSCs were present at both 2 and 4 weeks.

Conclusions: Platelet-rich plasma enhanced the effect of BMSC-seeded collagen gel interposition in this in vitro model. Based on these results, we now plan to investigate this effect in vivo.