Autologous Platelet Rich Plasma Injection Improves Early Tendon Repair in Rabbits: A Histopathological and Biomechanical Study

Objective- The aim of this study was to investigate the PRP effects on the early time-period during tendon healing in rabbits DDF tendon. Design-Experimental study Animals- Twenty male New Zealand white rabbits Procedure-PRP samples were prepared using twice centrifugation method of modification of the Cuarsan technique. Animals were randomly assigned into two equal treatment and control groups. The injury model was unilateral complete transection through the middle one third of deep digital flexor tendon. Immediately after primary repair, either 0.5 mL PRP or placebo was injected intratendiously into the suture site in the treatment and control groups, respectively. Operated limbs were immobilized for two weeks. Animals were sacrificed at the third week and the tendons underwent histopathological (H&E and MT staining) and biomechanical evaluation. Results- The histopathological (H&E) observation showed significant increase in percentage of fibrillar linearity, fibrillar continuity, number of capillaries in epitenon and epitenon thickness in PRP treated group compared to the control group (P<0.05). Results from MT staining revealed more collagen deposition, in treatment group in comparison with the control. Results of mechanical testing revealed the significant improvement of force at failure and energy absorption capacity of repair in the PRP group in comparison with the control (P<0.05). Conclusion and clinical relevance-The findings of the present study suggested that PRP was a simple, safe, quick and cost effective way to obtain a natural concentration of autologous growth factors which reduced the risk of rupture after tendon primary repair and improved functional outcomes.