Combined effects of photobiomodulation and platelet-rich plasma on healing of acute Achilles tendon injuries in rats.

Tendon injuries are challenging to treat due to limited intrinsic healing, and although photobiomodulation (PBM) and platelet-rich plasma (PRP) show therapeutic potential, their combined effects remain unclear. This study evaluated the individual and combined efficacy of PBM and PRP on Achilles tendon repair in rats. A total of 144 rats were assigned to six groups and treated with PBM, PRP, or combined PBM + PRP therapy; tissues were collected at 1 and 8 weeks for biochemical and histological assessment. Both PBM and PRP reduced IL-1β and TNF-α levels and improved collagen organization, while the combined therapy produced the most pronounced anti-inflammatory response and structural recovery. Notably, PBM + PRP significantly enhanced and prolonged PDGF-BB expression compared with either treatment alone. These findings demonstrate that PBM and PRP each promote tendon healing, but their combination yields superior therapeutic benefits through amplified modulation of inflammatory and regenerative pathways, highlighting their potential as an improved therapeutic strategy.