title: Erythropoietin stimulates patellar tendon healing in rats.
abstract: BACKGROUND
  Erythropoietin (EPO), regulating erythropoiesis, is used to provide protective and regenerative activity in non-haematopoietic tissues. There is insufficient knowledge about the role of EPO activity in tendon healing. Therefore, we investigated the effect of EPO treatment on healing in rat patellar tendons.
  
  
  METHODS
  One hundred and twenty-six, four-month-old male Sprague-Dawley rats were randomly assigned to three experimental groups: 1, no treatment; 2, treatment with isotonic saline (NaCl) and 3, treatment with EPO. Each group was randomly subdivided into two groups for sacrifice at three (1a, 2a, 3a) or six weeks (1b, 2b, 3b). Complete incision of the left patellar tendon from the distal patellar pole was performed. We applied body casts for 20 days after the incised edges of the patellar tendon were brought together with a surgical technique. Both legs were harvested and specimens from each group underwent histological, biomechanical, and protein mRNA expression analyses.
  
  
  RESULTS
  There were statistically significant differences in the ultimate breaking force between the EPO group and others at both weeks three and six (p<0.05); significant differences in fibroblast proliferation, capillary vessel formation, and local inflammation were found between groups 1a and 3a, and 2a and 3a (p<0.05). There were statistical differences between 1a, 3a and 2a, 3a for Col III, TGF-β1, and VEGF and between 1b, 3b and 2b, 3b for Col I, Col III, TGF-β1, and VEGF mRNA expressions.
  
  
  CONCLUSIONS
  EPO had an additive effect with surgery on the injured tendon healing process in rats compared to the control groups biomechanically, histopathologically and with tissue protein mRNA expression.
  
  
  CONCLUSIONS
  This is the first experimental study to analyze the relationship between EPO treatment and the patellar tendon repair process by biomechanical, histopathological, and tendon tissue mRNA expression methodologies.
authors.affiliation: Düzce University Medical School, Department of Orthopaedics and Traumatology, Düzce, Turkey. Electronic address: mustafauslu74@hotmail.com.
authors.forename: Mustafa
authors.initials: M
authors.lastname: Uslu
authors.affiliation: Düzce University Medical School, Department of Medical Pharmacology, Düzce, Turkey.
authors.forename: Ertuğrul
authors.initials: E
authors.lastname: Kaya
authors.affiliation: Kahramanmaras Sutcu Imam University, Faculty of Medicine, Department of Medical Biology, Kahramanmaras, Turkey.
authors.forename: Kürşat Oğuz
authors.initials: KO
authors.lastname: Yaykaşlı
authors.affiliation: Düzce University Medical School, Department of Pathology, Düzce, Turkey.
authors.forename: Murat
authors.initials: M
authors.lastname: Oktay
authors.affiliation: Sakarya University Medical School, Department of Orthopaedics and Traumatology, Sakarya, Turkey.
authors.forename: Mustafa Erkan
authors.initials: ME
authors.lastname: Inanmaz
authors.affiliation: Bolu Abant Izzet Baysal University Medical School, Department of Orthopaedics and Traumatology, Bolu, Turkey.
authors.forename: Cengiz
authors.initials: C
authors.lastname: Işık
authors.affiliation: Düzce University Medical School, Department of Pathology, Düzce, Turkey.
authors.forename: Havva
authors.initials: H
authors.lastname: Erdem
authors.affiliation: Düzce University Medical School, Department of Nuclear Medicine, Düzce, Turkey.
authors.forename: Melih Engin
authors.initials: ME
authors.lastname: Erkan
authors.affiliation: Düzce University Medical School, Department of First Aid and Emergency, Düzce, Turkey.
authors.forename: Hayati
authors.initials: H
authors.lastname: Kandiş
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004921:Erythropoietin / Q000494:pharmacology*; D008297:Male; D017847:Patellar Ligament / Q000187:drug effects / Q000293:injuries* / Q000601:surgery; D051381:Rats; D017207:Rats, Sprague-Dawley; D019651:Plastic Surgery Procedures / Q000379:methods*; D013708:Tendon Injuries / Q000188:drug therapy* / Q000601:surgery; D014945:Wound Healing / Q000187:drug effects*
chemical_list: D004921:Erythropoietin
keywords: Erythropoietin; Patellar tendon injury; Rat; Tendon healing