Platelet-Rich Fibrin Promotes an Accelerated Healing of Achilles Tendon When Compared to Platelet-Rich Plasma in Rat

BACKGROUND: Autologous platelet concentrate has been used to improve the function and regeneration of injured tissues. Tendinopathies are common in clinical practice, although long-term treatment is required. On the basis of lead time, we compared the effect of using platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) in repairing rat Achilles tendon. METHODS: The effectiveness of using PRP and PRF was evaluated after 14 and 28 postoperative days by histological analysis. The quantification of collagen types I and III was performed by Sirius red staining. Qualitatively, the data were verified with hematoxylin-eosin (H&E) staining. RESULTS: In Sirius red staining, no significant treatment differences were found between groups. Statistical difference was observed only between PRP (37.2% collagen) and the control group (16.2%) 14 days after treatment. Intra-groups compared twice showed a difference for collagen I (27.8% and 47.7%) and III (66.9% and 46.0%) in the PRF group. The control group showed differences only in collagen I (14.2% and 40.9%) and no other finding was observed in the PRP group. In H&E staining, PRF showed a better cellular organization when compared to the other groups at 28 days. CONCLUSION: Our study suggests that PRF promotes accelerated regeneration of the Achilles tendon in rats, offering promising prospects for future clinical use.