title: A single dose of platelet-rich plasma improves the organization and strength of a surgically repaired rotator cuff tendon in rats.
abstract: BACKGROUND
  Rotator cuff tear (RCT) is a common cause of pain and disability among adults. Platelet-rich plasma (PRP) is a fraction of whole blood containing concentrated growth factors and proteins important for tissue healing. This study aimed at investigating the effects of local autologous PRP injection on repaired rotator cuff (RC) tendon repair in rats.
  
  
  METHODS
  Following experimental RCT and suturing, 44 Wistar rats were randomly allocated into two groups: (1) RC repair only (controls); (2) RC repair + PRP administration-shoulders were treated with intra-articular PRP immediately after the repair. Animals were killed after 3 weeks and tendon, were tested biomechanically in tension (12 rats/group). The remaining tendons (10 rats/group) were stained using hematoxylin and eosin and Picro-sirius Red. Histological analysis evaluated the cellular aspects of the repair tissue.
  
  
  RESULTS
  PRP administration following experimental RC tear and suture resulted in a significantly higher maximal load (p < 0.001) and stiffness (p < 0.005) as compared to non-treated animals. Bonar score of PRP-treated tendons was significantly better (p = 0.018) than the control group. Collagen birefringence was significantly higher in PRP shoulders (p = 0.002), indicating improved organization. Vascularity scores were similar in both groups.
  
  
  CONCLUSIONS
  Application of a single dose autologous PRP in adjunct to surgical repair resultes in improved tendon-to-bone healing, assessed by histological and biomechanical testing in a rat model of acute RCT, when tested at 3 weeks compared to controls. Further studies will be essential to determine the role of PRP in clinical practice.
authors.affiliation: Shoulder Unit, Division of Orthopaedic Surgery, Tel Aviv Sourasky Medical Center, 6 Weizman Street, 64239, Tel Aviv, Israel, dolkarto@gmail.com.
authors.forename: Oleg
authors.initials: O
authors.lastname: Dolkart
authors.forename: Ofir
authors.initials: O
authors.lastname: Chechik
authors.forename: Yaron
authors.initials: Y
authors.lastname: Zarfati
authors.forename: Tamar
authors.initials: T
authors.lastname: Brosh
authors.forename: Fadi
authors.initials: F
authors.lastname: Alhajajra
authors.forename: Eran
authors.initials: E
authors.lastname: Maman
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D003131:Combined Modality Therapy; D007430:Intraoperative Care; D008297:Male; D019637:Orthopedic Procedures / Q000379:methods*; D053657:Platelet-Rich Plasma; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D017006:Rotator Cuff / Q000473:pathology / Q000502:physiology / Q000601:surgery; D000070636:Rotator Cuff Injuries; D013708:Tendon Injuries / Q000601:surgery*; D016896:Treatment Outcome; D014945:Wound Healing / Q000502:physiology