Comparison of the effect of intra‐tendon applications of recombinant human platelet‐derived growth factor‐BB,platelet‐rich plasma,steroids in a rat achilles tendon collagenase model

This study compared the effect of intra‐tendon (IT) delivery of recombinant human platelet‐derived growth factor‐BB (rhPDGF‐BB), platelet‐rich plasma (PRP) and corticosteroids in a rat tendinopathy model. Seven days after collagenase induction of tendinopathy, a 30‐µl IT injection was administered. Treatments included: saline; 3 µg rhPDGF‐BB; 10 µg rhPDGF‐BB; PRP; and 300 µg triamcinolone acetonide (TCA). Outcomes were assessed 7 and 21 days after treatment. All groups exhibited good to excellent repair. Relative to saline, cell proliferation increased 65% in the 10 µg rhPDGF‐BB group and decreased 74% in the TCA group; inflammation decreased 65% in the TCA group. At 7 days, maximum load‐to‐failure was increased in the 3 µg rhPDGF‐BB group relative to saline, PRP, and TCA (p < 0.025). On day 21, maximum load‐to‐rupture was increased in the 10 µg rhPDGF‐BB group relative to saline, PRP, and TCA (p < 0.035) and in the 3 µg rhPDGF‐BB group compared to saline and TCA (p < 0.027). Stiffness in the 10 µg rhPDGF‐BB group was increased compared to saline, PRP, and TCA (p < 0.038). Histology demonstrated similar repair in all groups. PRP and TCA did not improve mechanical properties compared to saline. Injections of rhPDGF‐BB increased maximum load‐to‐failure (3 and 10 µg) and stiffness (10 µg) relative to controls and commonly used treatments. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:145–150, 2014.