title: Analysis of rat calvaria defects implanted with a platelet-rich plasma preparation: radiographic observations.
abstract: BACKGROUND
  Platelet-rich plasma (PRP) harbors growth factors identified in bone. It has been suggested that these factors enhance osteogenesis. The objective of this study was to conduct a radiographic evaluation on local bone formation following surgical implantation of a PRP preparation using a critical-size rat calvaria defect model.
  
  
  METHODS
  Thirty 22-week-old 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) carrier or ACS alone was surgically implanted into contralateral critical-size 6 mm rat calvaria osteotomies in 18 animals. Twelve animals received ACS alone versus sham surgery in contralateral defects. Animals were sacrificed at 4 and 8 weeks when biopsies were collected and radiographs were obtained using a standardized protocol. Three masked examiners independently evaluated the radiographic images of the defect sites. Examiner reproducibility was examined by repeat evaluation of all defect sites (r=0.6; P <0.0001).
  
  
  RESULTS
  The animals were maintained without adverse events. Defect sites in two animals receiving ACS versus sham surgery (4-week healing interval) were not evaluated due to specimen damage. Seventy-five percent of the sites (PRP/ACS or ACS) exhibited partial closure at 4 weeks; one site (ACS) exhibited full closure without significant differences between protocols (P=0.1797). Fifty percent of the sites receiving PRP/ACS exhibited full closure and 20% partial closure at 8 weeks versus 20% and 80%, respectively, for the ACS control (P=0.7532). There were no noteworthy differences between sites receiving ACS versus sham surgery at 4 or 8 weeks.
  
  
  CONCLUSIONS
  The results suggest that the PRP preparation does not have a significant effect on osteogenesis.
authors.affiliation: Laboratory for Applied Periodontal and Craniofacial Regeneration, Department of Periodontology, Temple University School of Dentistry, Philadelphia, PA 19140, USA. wikesjo@comcast.net
authors.forename: Mary E
authors.initials: ME
authors.lastname: Pryor
authors.forename: Jie
authors.initials: J
authors.lastname: Yang
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: Alexis
authors.initials: A
authors.lastname: Agelan
authors.forename: Joanne M
authors.initials: JM
authors.lastname: Manns
authors.forename: Ulf M E
authors.initials: UM
authors.lastname: Wikesjö
mesh_terms: D000818:Animals; D001792:Blood Platelets; D001861:Bone Regeneration / Q000187:drug effects*; D003399:Craniotomy; D004337:Drug Carriers; D005781:Gelatin Sponge, Absorbable; D006133:Growth Substances / Q000494:pharmacology; D008297:Male; D010956:Plasmapheresis; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D012886:Skull / Q000601:surgery
chemical_list: D004337:Drug Carriers; D006133:Growth Substances