The study on the construction of injectable tissue-engineered bone based on the injectable PRF combined with osteoblastic bone marrow mesenchymal stem cell sheets

Injectable platelet-rich fibrin (i-PRF) has been proven to be able to promote tissue regeneration and applied in the treatment of diseases in the maxillofacial region, but whether it can be used to construct injectable tissue-engineered bone remains inconclusive. The aim of this study was to investigate whether i-PRF combined with osteoblastic bone marrow mesenchymal stem cell (BMSC) sheets can be used to construct injectable tissue-engineered bone. First, i-PRF prepared from fresh blood after a short-time and low-speed centrifugation. BMSCs, after continuous osteogenic induction for 2 weeks, formed membrane-like structures containing calcium nodules. They were mixed and then transplanted subcutaneously in nude mice by injection. the osteogenesis was evaluated through Micro-CT scanning and histological analysis after 8 weeks of transplantation. The group with BMSC sheets alone formed osteoid tissue, but the volume of new bone- and cartilage-like tissue was smaller, more sparse, and unevenly distributed. In contrast, the group with i-PRF and BMSC sheets had larger volumes of new tissue, higher bone density, more mineralized deposits, and more woven bone structures. In summary, osteoblastic BMSC sheets have the potential for ectopic osteogenesis, but i-PRF can significantly enhance their osteogenic capacity. Therefore, i-PRF combined with osteoblastic BMSC sheets can be regarded as a promising method for constructing injectable tissue-engineered bone.