Freeze-Dried Platelet-Rich Plasma Accelerates Bone Union with Adequate Rigidity in Posterolateral Lumbar Fusion Surgery Model in Rats

Abstract

Fresh platelet-rich plasma (PRP) accelerates bone union in rat model. However, fresh PRP has a short half-life. We suggested freeze-dried PRP (FD-PRP) prepared in advance and investigated its efficacy in vivo. Spinal posterolateral fusion was performed on 8-week-old male Sprague-Dawley rats divided into six groups based on the graft materials (n = 10 per group): sham control, artificial bone (A hydroxyapatite–collagen composite) –alone, autologous bone, artificial bone + fresh-PRP, artificial bone + FD-PRP preserved 8 weeks, and artificial bone + human recombinant bone morphogenetic protein 2 (BMP) as a positive control. At 4 and 8 weeks after the surgery, we investigated their bone union–related characteristics including amount of bone formation, histological characteristics of trabecular bone at remodeling site, and biomechanical strength on 3-point bending. Comparable radiological bone union was confirmed at 4 weeks after surgery in 80% of the FD-PRP groups, which was earlier than in other groups (p < 0.05). Histologically, the trabecular bone had thinner and more branches in the FD-PRP. Moreover, the biomechanical strength was comparable to that of autologous bone. FD-PRP accelerated bone union at a rate comparable to that of fresh PRP and BMP by remodeling the bone with thinner, more tangled, and rigid trabecular bone.

Freeze-Dried Platelet-Rich Plasma Induces Osteoblast Proliferation via Platelet-Derived Growth Factor Receptor-Mediated Signal Transduction

“…To overcome this limitation, we focused on freeze-dried PRP (FD-PRP) and confirmed that FD-PRP maintained baseline levels of GFs for the entire 8-week duration [12]. Furthermore, Shiga et al [13] showed that FD-PRP could achieve accelerated bone union in a rat PLF model even after 8-week storage. However, there is no report showing the pharmacological activity of GFs, such as PDGF, in FD-PRP in storage for a long-term period.…”

A level‐set method for the evolution of cells and tissue during curvature‐controlled growth

“…To represent a realistic geometric situation, we take for initial interface the surface of a single trabecular bone spicule seen in an experimental cross‐section . We then consider the apposition of new bone layers on this surface, as would occur, for example, by bone mechanical adaptation .…”

“…Bone deposition around a single trabecular spicule obtained using Methods 2 (left column) 3 (right column). The initial shape of trabecular spicule is extracted from a previous study (, figure ). The interface is shown at regular time intervals of 0.24 days and coloured according to the interface velocity (top row).…”

“…Figure shows simulations of bone resorption (top row) and bone apposition (bottom row) from an initial bone interface extracted from a histological section of trabecular bone from Shiga et al Bone apposition leads to fusion of initially distinct trabecular spicules, while bone resorption leads to their fragmentation, as would occur for instance during osteoporotic or age‐related bone loss . We note that during bone resorption, some trabecular spicules disappear, leading to an inevitable loss of cells that is not entirely due to numerical inaccuracies, see Figure S2.…”

“…Time snapshots of the concurrent evolution of several trabecular spicules from an experimental image under bone resorption (top) and bone formation (bottom). Simulation parameters: Method 3, v 0 =10 −3 mm/d, A =0, D =0.0001 mm 2 /day, ϵ reinit =600, Δ x =Δ y =0.0086 mm, Δ t =0.0023 days…”