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

Abstract

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.

Impact Statement

This study demonstrates that the platelet-rich plasma (PRP)/calcium phosphate bone cement (CPC) composite prepared via CPC-PRP combination has a significantly prolonged setting time, enhanced injectability and washout resistance, and remarkable rheological properties. It exhibits superior biomechanical properties in repair of vertebral bone injuries by increasing vertebral strength and stiffness. This innovation provides a robust scientific foundation for the clinical application of the PRP/CPC composite in addressing load-bearing bone defects in critical anatomical regions such as the vertebrae.