Analysis of rat calvaria defects implanted with a platelet-rich plasma preparation: radiographic observations.
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.
Pryor
Mary E
ME
Laboratory for Applied Periodontal and Craniofacial Regeneration, Department of Periodontology, Temple University School of Dentistry, Philadelphia, PA 19140, USA. wikesjo@comcast.net
Yang
Jie
J
Polimeni
Giuseppe
G
Koo
Ki-Tae
KT
Hartman
Michael J
MJ
Gross
Howard
H
Agelan
Alexis
A
Manns
Joanne M
JM
Wikesjö
Ulf M E
UM
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
D004337:Drug Carriers; D006133:Growth Substances