Repair of Vertebral Bone Defects with Injectable Calcium Phosphate Bone Cement Reinforced with Autologous Platelet-rich Plasma in Goats

Platelet-rich plasma (PRP) was prepared from goat blood using a modified Landesberg method. A PRP/calcium phosphate bone cement (CPC) composite paste was then prepared by combining PRP with injectable CPC, whereby the platelet counts in PRP increased by about 5.9-fold compared to that in the whole blood. Additionally, the levels of PDGF-AB, TGF-β, and VEGF in PRP were significantly higher than those in the whole blood. The new PRP/CPC composite exhibited significantly better injectability, initial setting time, final setting time, and washout resistance compared with CPC alone. A lumbar vertebral defect model was established in 18 Hainan indigenous male black goats via a retroperitoneal approach. Six lumbar vertebrae from each goat were randomized to three groups: a control group receiving normal saline, a CPC group using CPC paste alone, and a PRP/CPC group treated with the autologous PRP/CPC composite paste. The goats were maintained under standard feeding conditions postoperatively. Six goats were euthanized at 1, 3, and 6 months after operation to obtain vertebral specimens for assessment of vertebral strength and stiffness. Digital radiographical imaging at 6 months after operation showed that the vertebrae had normal growth and morphology in all groups. At 1, 3, and 6 months after operation, the vertebral strength and stiffness in PRP/CPC group were significantly greater than those in CPC-alone group. In addition, both vertebral strength and stiffness showed further improvement with the extension of postoperative recovery time. The PRP/CPC composite exhibited commendable rheological properties, and its application in repair of vertebral bone defects yielded favorable biomechanical properties. Furthermore, the new autologous PRP/CPC composite showed excellent biocompatibility and tissue repair capability and may prove to be a suitable candidate for repair of load-bearing bone defects, particularly those present in vertebrae.