title: Impact of platelet-rich plasma injection timing on healing of Achilles tendon injury in a rat model.
abstract: OBJECTIVE
  The aim of this study was to evaluate the impact of the timing of platelet-rich plasma (PRP) application on the healing of Achilles tendon injury in a rat model.
  
  
  METHODS
  Fifty-four female Sprague-Dawley rats were divided into 4 groups: PRP preparation group (n=6); Achilles tendon tear and 150 µL of PRP received on the day following the injury (PRP day 0, group 1, n=16); Achilles tendon tear and 150 µL of PRP received on the third day following injury (day 3 , group 2, n=16); Achilles tendon tear and 150 µL of saline received on the day following injury (PRP day 0, group 3, n=16). Rats were sacrificed at 3 weeks. Consequently, biomechanical and histologic analyses were performed.
  
  
  RESULTS
  According to histological evaluation, inflammation, fibroblast density, epitenon thickness, and collagen fiber were significantly higher in group 1 than in group 2 (p<0.05). Biomechanical testing results of group 1 and group 2 were inferior to the control group, while the differences were not significant (p>0.05).
  
  
  CONCLUSIONS
  Based on histological criteria, results of the present study suggest that immediate injection of PRP for tendon injury improves tendon healing in rats. Although the use of PRP is well recognized in orthopedic surgery, we aimed to highlight the importance of immediate application of PRP for acute tendon injury.
authors.affiliation: İstanbul Training and Research Hospital, Department of Orthopaedics and Traumatology, İstanbul, Turkey. esracirci@hotmail.com.
authors.forename: Esra
authors.initials: E
authors.lastname: Çirci
authors.affiliation: Baltalimanı Bone Diseases Training and Research Hospital, Department of Orthopaedics and Traumatology, İstanbul, Turkey.
authors.forename: Yunus Emre
authors.initials: YE
authors.lastname: Akman
authors.affiliation: İstanbul Training and Research Hospital, Department of Orthopaedics and Traumatology, İstanbul, Turkey.
authors.forename: Erhan
authors.initials: E
authors.lastname: Şükür
authors.affiliation: İstanbul Training and Research Hospital, Department of Pathology, İstanbul, Turkey.
authors.forename: Erol Rüştü
authors.initials: ER
authors.lastname: Bozkurt
authors.affiliation: İstanbul Training and Research Hospital, Department of Orthopaedics and Traumatology, İstanbul, Turkey.
authors.forename: Tolga
authors.initials: T
authors.lastname: Tüzüner
authors.affiliation: İstanbul Training and Research Hospital, Department of Orthopaedics and Traumatology, İstanbul, Turkey.
authors.forename: Yusuf
authors.initials: Y
authors.lastname: Öztürkmen
mesh_terms: D000125:Achilles Tendon / Q000293:injuries*; D000818:Animals; D001696:Biomechanical Phenomena; D004195:Disease Models, Animal; D005260:Female; D007267:Injections; D053657:Platelet-Rich Plasma; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014945:Wound Healing