title: Analysis of rat calvaria defects implanted with a platelet-rich plasma preparation: histologic and histometric observations.
abstract: OBJECTIVE
  It has been suggested that degranulating platelet alpha-granules release growth factors having a potential to modulate bone formation. The objective of this study was to evaluate the osteoconductive potential of a platelet-rich plasma (PRP) preparation.
  
  
  METHODS
  Thirty adult male Sprague-Dawley rats were used. The PRP preparation was obtained from 10 ml of whole blood drawn from one age-matched donor rat. The preparation was processed by gradient density centrifugation and stored at -80 degrees C until use. Using aseptic techniques, the PRP preparation soak loaded onto an absorbable collagen sponge (ACS) or ACS alone was surgically implanted into contralateral critical size 6-mm calvaria osteotomies in 18 animals. Twelve animals received ACS versus sham surgery in contralateral defects. Animals were sacrificed at 4 and 8 weeks when biopsies were collected for histologic and histometric analysis.
  
  
  RESULTS
  The animals were maintained without adverse events. Bone formation was highly variable in sites receiving PRP and control treatments. Defect bone fill at 4 weeks averaged (+/-SD) 28.8+/-27.4% (PRP/ACS) versus 39.1+/-24.4% (ACS; p=0.2626) and 62.0+/-20.0% (ACS) versus 71.6+/-32.2% (sham surgery; p=0.1088), and at 8 weeks 81.0+/-12.9% (PRP/ACS) versus 64.5+/-28.1% (ACS; p=0.2626) and 75.6+/-34.1% (ACS) versus 74.1+/-24.2% (sham surgery; p=0.7353). Remnants of the ACS biomaterial were observed at both 4 and 8 weeks in sites implanted with PRP/ACS or ACS.
  
  
  CONCLUSIONS
  The results suggest that the PRP preparation has a limited potential to promote local bone formation.
authors.affiliation: Laboratory for Applied Periodontal and Craniofacial Regeneration, Department of Periodontology, Temple University School of Dentistry, Philadelphia, PA 19140, USA.
authors.forename: Mary E
authors.initials: ME
authors.lastname: Pryor
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Polimeni
authors.forename: Ki-Tae
authors.initials: KT
authors.lastname: Koo
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Hartman
authors.forename: Howard
authors.initials: H
authors.lastname: Gross
authors.forename: Milton
authors.initials: M
authors.lastname: April
authors.forename: Fayez F
authors.initials: FF
authors.lastname: Safadi
authors.forename: Ulf M E
authors.initials: UM
authors.lastname: Wikesjö
mesh_terms: D000818:Animals; D001792:Blood Platelets; D001861:Bone Regeneration / Q000187:drug effects / Q000502:physiology*; D018786:Bone Substitutes / Q000627:therapeutic use*; D003094:Collagen / Q000627:therapeutic use*; D008297:Male; D010027:Osteotomy; D051381:Rats; D017207:Rats, Sprague-Dawley; D012886:Skull / Q000033:anatomy & histology / Q000502:physiology / Q000601:surgery*; D018709:Statistics, Nonparametric; D014945:Wound Healing / Q000187:drug effects / Q000502:physiology*
chemical_list: D018786:Bone Substitutes; D003094:Collagen