title: Experimental model for the study of the effects of platelet-rich plasma on the early phases of muscle healing.
abstract: BACKGROUND
  There is abundant evidence suggesting that growth factors may play a key role in the healing process, especially in the early stages of inflammation. Despite the reported clinical successes with the use of growth factors there is still a lack of knowledge on the biological mechanism underlying the activity of platelet-rich plasma during the process of muscle healing. The aim of this study was to analyse the early effects of platelet- rich plasma in an easily reproducible animal model.
  
  
  METHODS
  Wistar male adult rats (n=102) were used in this study. The muscle lesion was created with a scalpel in the flexor sublimis muscles. Platelet-rich plasma was applied immediately after surgery. Treated, untreated and contralateral muscles were analysed by morphological evaluation and western blot assay.
  
  
  RESULTS
  Leucocyte infiltration was significantly greater in muscles treated with platelet-rich plasma than in both untreated and contralateral muscles. The latter showed greater leucocyte infiltration when compared to the untreated muscles. Platelet-rich plasma treatment also modified the cellular composition of the leucocyte infiltration leading to increased expression of CD3, CD8, CD19 and CD68 and to decreased CD4 antigen expression in both platelet-rich plasma treated and contralateral muscles. Blood vessel density and blood vessel diameters were not statistically significantly different between the three groups analysed.
  
  
  CONCLUSIONS
  The results of this study showed that treatment with platelet-rich plasma magnified the physiological early inflammatory response following a muscle injury, modifying the pattern of cellular recruitment. Local platelet-rich plasma treatment may exert a direct or, more plausibly, indirect systemic effect on healing processes, at least in the earliest inflammatory phase.
authors.affiliation: Department of Health Sciences, University of Rome "Foro Italico", Rome, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Borrione
authors.affiliation: Department of Health Sciences, University of Rome "Foro Italico", Rome, Italy.
authors.forename: Loredana
authors.initials: L
authors.lastname: Grasso
authors.affiliation: Department of Health Sciences, University of Rome "Foro Italico", Rome, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Chierto
authors.affiliation: Department of Clinical and Biological Sciences, University of Turin, Turin, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Geuna
authors.affiliation: Department of Clinical and Biological Sciences, University of Turin, Turin, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Racca
authors.affiliation: Department of Clinical and Biological Sciences, University of Turin, Turin, Italy.
authors.forename: Giuliana
authors.initials: G
authors.lastname: Abbadessa
authors.affiliation: Department of Clinical and Biological Sciences, University of Turin, Turin, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Ronchi
authors.affiliation: Department of Health Sciences, University of Rome "Foro Italico", Rome, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Faiola
authors.affiliation: Department of Health Sciences, University of Rome "Foro Italico", Rome, Italy.
authors.forename: Alessia
authors.initials: A
authors.lastname: Di Gianfrancesco
authors.affiliation: Department of Health Sciences, University of Rome "Foro Italico", Rome, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Pigozzi
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000096:biosynthesis / Q000235:genetics; D001781:Blood Component Removal; D002634:Chemotaxis, Leukocyte; D005786:Gene Expression Regulation; D007962:Leukocytes / Q000378:metabolism / Q000473:pathology; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply / Q000293:injuries* / Q000473:pathology; D009220:Myositis / Q000209:etiology / Q000628:therapy; D018919:Neovascularization, Physiologic; D053657:Platelet-Rich Plasma; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results; D015854:Up-Regulation; D014945:Wound Healing / Q000187:drug effects*
chemical_list: D015703:Antigens, CD