Platelet-Derived Extracellular Vesicle - Rich Plasma Demonstrates Favorable Histological Features Compared With PRP...

Platelet-rich plasma (PRP) is commonly used to support skeletal muscle healing, although its efficacy remains variable and concerns persist regarding profibrotic effects. Platelet-derived extracellular vesicles (pEVs) may modulate inflammation, and this study aimed to compare the histological effects of two PRP systems and a pEV-rich plasma preparation in a rabbit muscle injury model. A standardized partial muscle injury (5 × 5 mm) was created in the biceps femoris of 28 female New Zealand White rabbits. Animals were allocated to four groups: control, Arthrex ACP®, T-LAB PRP®, and platelet-derived extracellular vesicle-rich plasma (Exomine®). Treatments were administered locally on postoperative days 0, 4, and 7. Half of the animals were euthanized at week 3 and the remainder at week 6. Histological evaluation focused on inflammatory infiltration, fibrotic scar formation, and indicators of muscle regeneration. At week 3, overall group comparisons showed significant differences in acute inflammatory parameters, with the pEV-rich plasma group exhibiting lower neutrophil infiltration and fewer multinucleated giant cells. At week 6, significant differences were observed in chronic inflammation and remodeling, with reduced lymphocyte-macrophage infiltration and fibrosis in the pEV-rich plasma group. Both PRP groups showed histological findings comparable to control. In this preclinical rabbit model, a platelet-derived extracellular vesicle-rich plasma preparation was associated with more favorable histological features related to inflammation resolution and fibrosis than conventional PRP. These findings are limited to histopathological outcomes and require confirmation with functional studies.