Single injection of platelet-rich plasma in a rat Achilles tendon tear model.

: The purpose of this study was to determine the efficacy of platelet-rich plasma (PRP) 1-injection during an Achilles tendon rat tear model. 80 male adult imbreded rats (Wistar Kyoto), underwent under surgical tendon rupture. 40 Animal (PRP group rats) were given a local injection with 0,25 mL of PRP, and 40 animal (control group) were given the same quantity of control solution. The rats were sacrified at 1, 2, 4 and 6 weeks (each time point, 20 rats of the each group) after surgical tear and tendon tissue was analysed by macroscopic aspect, histology, immunostaining and Real Time (RT)-PCR to evaluate tissue repair. PRP improved tendon remodelling by better coordination of the reconstructive process with earlier formation of tendon-like continuity only in the first week after surgery. However, after 2,4 and 6 weeks, Achilles tendons in the PRP group had no difference compared to the control group. Immunostaining and RT-PCR did not show any difference between PRP treated and untreated group. Based on these findings a single injection of PRP appear not useful for Achilles rat tendon tear.