Osteogenic differentiation of muscle satellite cells induced by platelet-rich plasma encapsulated in three-dimensional alginate scaffold.

OBJECTIVE: Osteogenic potential of muscle satellite cells (MSCs) makes them a possible source of seeding cells for bone tissue engineering. The objective of the present study was to determine the effects of platelet-rich plasma (PRP) on proliferation and osteogenic differentiation of MSCs by encapsulation of PRP into 3-dimensional alginate hydrogel in vitro and in vivo. STUDY
DESIGN: PRP was obtained from Sprague-Dawley rats using 2 centrifugation techniques. MSCs were expanded and differentiated in the presence or absence of PRP in monolayer and 3-dimensional cultures. Cell viability was evaluated with the use of an MTT proliferation assay after 1, 7, 14, and 21 days of stimulation. Alkaline phosphatase (ALP) activity, calcium deposition, and real-time reverse-transcription polymerase chain reaction (RT-PCR) of osteogenic-related genes were performed to study the effects of PRP on osteogenic differentiation of cultured MSCs by encapsulation of PRP in alginate gel. For in vivo study, the PRP-MSCs-alginate gel mixture was implanted in subcutaneous pockets of nude mice to examine the ectopic bone formation at 2 weeks.
RESULTS: After 1, 7, 14, and 21 days of stimulation, PRP significantly promoted MSC proliferation in PRP-alginate gel mixture cultures. ALP activity, calcium deposition, and real-time RT-PCR showed enhanced cell osteogenic differentiation in the PRP-alginate group. Histologic examination demonstrated that large amount of fibrous tissue capsule, collagen, and new vascular growth were detected in the PRP-MSCs-alginate group compared with the alginate and MSCs-alginate groups.
CONCLUSIONS: The results of this study suggest that MSCs induced by PRP encapsulated in an alginate gel mixture can undergo induction into osteoblastic phenotype both in vitro and in vivo, which makes the production of PRP-enhanced tissue-engineered bone using MSCs possible.