Effect of leukocyte and platelet-rich plasma on osseointegration after implant placement in mouse maxilla

Introduction: Osseointegration, the direct contact between an implant and bone, can be achieved by direct and/or indirect osteogenesis. Platelet-rich plasma accelerates tissue regeneration, wound healing, and osseointegration. This study aimed to analyze the effects of leukocyte and platelet-rich plasma (LPRP) on direct and indirect osteogenesis after implant placement in a mouse maxilla. Methods: Blood was collected from the tail vein of 4-8-week-old male ICR mice and L-PRP was obtained after double-spin cycle centrifugation. After the right upper first molars of 4-week-old ICR mice were extracted while under deep anesthesia, the alveolar sockets were prepared with a drill, and titanium implants blasted with hydroxyapatite/(3-tricalcium phosphate were placed into the cavity filled with 1.5 mL of L-PRP. Samples were collected from the animals 3-28 days after implantation, and immunohistochemistry for osteopontin, Ki67 (cell proliferation marker), cathepsin-K (osteoclast marker), and osteonectin (osteoblast marker) was performed. Results: Cell proliferation was significantly higher in the L-PRP group than in the control group on postoperative days 3 and 5. The activities of osteoclast-lineage cells and osteoblasts increased significantly on day 5 in the L-PRP group, indicating that L-PRP evoked an active cellular response. Indirect osteogenesis was significantly higher on days 7, 14, and 28, and the osseointegration rate was significantly higher on day 28 in the L-PRP group compared with the control group. Conclusions: L-PRP enhances osseointegration by promoting mesenchymal cell proliferation, osteoclastic and osteoblastic activities, and indirect osteogenesis. (c) 2024 The Author(s). Published by Elsevier BV on behalf of The Japanese Society for Regenerative Medicine. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/lice nses/by-nc-nd/4.0/).