Platelet-poor plasma stimulates the proliferation but inhibits the differentiation of rat osteoblastic cells in vitro.
BACKGROUND
Recent studies have shown that the use of platelet preparations in bone and implant surgery might stimulate bone formation. However, the biological mechanisms are not well understood. Moreover, few studies have attempted to evaluate the effect of platelet-poor plasma (PPP), which is a product of the platelet-rich plasma preparation process.


OBJECTIVE
Thus, this study investigated the behavior of osteoblasts isolated from fetal rat calvaria cultivated in the presence of homologous PPP.


METHODS
PPP was obtained by centrifugation of the rat mother's blood and used in replacement of fetal calf serum, which is classically used in primary culture procedures. Proliferation was measured by an MTT assay at 24, 48, and 72 h. Real-time PCR was performed to study the expression of Runx2, Dlx5, and osteocalcin (OC) on days 0 (4 h), 1, 3, 7, and 12.


RESULTS
Alkaline phosphatase (ALP) biochemical activity was evaluated on days 0 (4 h), 1, 3, 7, and 12. Observations by phase-contrast microscopy showed that osteoblasts were able to differentiate until the mineralization of the matrix in the presence of PPP. PPP enhanced the proliferation significantly compared with the control group (P< or =0.001). PCR results showed that Runx2, Dlx5, and OC were expressed by cells in the experimental group at lower levels compared with the control group. Biochemical assay of ALP showed a lower activity in the experimental group compared with the control group (P<0.001).


CONCLUSIONS
These results suggest that, in the presence of homologous PPP, rat osteoblastic cells are able to maintain their phenotype, with a higher rate of proliferation. However, PPP seems to inhibit osteoblastic differentiation.
Hamdan
Ahmad Abdel-Salam
AA
INSERM, U872, Eq. 5, Laboratoire de Physiopathologie Orale Moléculaire, Paris, France. ahmoodi@hotmail.com
Loty
Sabine
S
Isaac
Juliane
J
Bouchard
Philippe
P
Berdal
Ariane
A
Sautier
Jean-Michel
JM
D000469:Alkaline Phosphatase / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D001792:Blood Platelets / Q000166:cytology / Q000502:physiology*; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D003470:Culture Media / Q000494:pharmacology; D010006:Osteoblasts / Q000502:physiology*; D015675:Osteocalcin / Q000187:drug effects / Q000378:metabolism; D010949:Plasma / Q000166:cytology / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014157:Transcription Factors / Q000187:drug effects / Q000378:metabolism
D003470:Culture Media; D014157:Transcription Factors; D015675:Osteocalcin; D000469:Alkaline Phosphatase