Platelet-rich plasma activates tendon-derived stem cells to promote regeneration of Achilles tendon rupture in rats.

This study investigates whether platelet-rich plasma (PRP) is an activator of tendon-derived stem cells (TDSCs) to promote regeneration of Achilles tendon post-rupture in rats. In the in vitro study, PRGF (activated PRP) significantly enhanced cell DNA synthesis, improved viability and promoted proliferation, while facilitating cell migration and the recruitment of TDSCs. In addition, TDSCs were mixed with collagen and PRP to form collagen-TDSC constructs (CTC) and PRP-collagen-TDSC constructs (PCTCs). After 3 weeks of culture in vitro, we found that most of the encapsulated TDSCs in the CTCs and PCTCs were still alive, while cells in the PCTCs showed a more aligned arrangement compared to the CTCs. In addition, the micro-structure of PCTC showed more obvious fibre-like tissues and formed a cyclic microvascular structure. The tenocyte-related genes types I and III collagen, Tenascin-C and Scleraxis of TDSCs in the PCTCs and CTCs were upregulated with time, and PCTCs showed more significance than CTCs (p < 0.05). After in vivo transplantation, the CTCs and PCTCs showed stimulatory effects on Achilles tendon healing. Moreover, the PCTCs improved the macroscopic appearance, histological morphology and biomechanical strength of ruptured Achilles tendon better than CTC. These results indicate that PRP can activate TDSCs to improve the quality of Achilles tendon rupture healing in the early stages.