LAUSR

Purpose Non-activated platelet-rich plasma (nPRP) slowly releases growth factors that induce bone regeneration. Adipose tissue-derived stem cells (ASCs) are also known to induce osteoblast differentiation. In this study, we investigated the combined effect of nPRP and ASC treatment compared with single therapy on bone regeneration. Methods Thirty New Zealand white rabbits with 15 × 15 mm 2 calvarial defects were randomly divided into four treatment groups: control, nPRP, ASC, or nPRP + ASC groups. For treatment, rabbits received a collagen sponge (Gelfoam®) saturated with 1 ml normal saline (controls), 1 ml non-activated PRP (nPRP group), 2 × 10 6 ASCs (ASCs group), or 2 × 10 6 ASCs plus l ml nPRP (nPRP + ASCs group). After 16 weeks, bone volume and new bone surface area were measured, using three-dimensional computed tomography and digital photography. Bone regeneration was also histologically analyzed. Results Bone surface area in the nPRP group was significantly higher than both the control and ASC groups ( p  < 0.001 and p  < 0.01, respectively). The percentage of regenerated bone surface area in the nPRP + ASC group was also significantly higher than the corresponding ratios in the control group ( p  < 0.001). The volume of new bone in the nPRP group was increased compared to the controls ( p  < 0.05). Conclusion Our results demonstrate that slow-releasing growth factors from nPRP did not influence ASC activation in this model of bone healing. PRP activation is important for the success of combination therapy using nPRP and ASCs.