Platelet-rich plasma concentrations regulate MSCs osteogenesis via MAPK/PI3K–AKT pathways to mitigate inflammatory bone loss

Bone maintains a dynamic and stable state through the orchestration of osteoclasts and osteoblasts. Osteoblasts are derived mainly from mesenchymal stem cell (MSC) and are responsible for bone formation. The inhibition of osteoblast proliferation and differentiation is involved in many diseases, including osteoporosis, osteoarthritis, infected bone defects, and inflammatory aseptic loosening of implants. Given the currently limited treatment options, exploring new methods to promote bone formation is an important focus significant for orthopedists. Platelet-rich plasma (PRP), an autologous substance that is rich in various growth factors, is widely used in regenerative medicine. However, the effect of PRP on inflammatory bone destruction remains unclear. We investigated the effects of PRP on the viability of MSC, and the impact of different concentrations of PRP (1% and 3%, respectively) on cell death, proliferation, and differentiation. Furthermore, we tested the therapeutic effect of different concentrations of PRP (1% and 3%) on LPS-induced inflammatory bone destruction in vivo. PRP enhanced the cellular activity of MSC and promoted osteogenesis. A higher concentration of PRP (3%) primarily reduced the death and increased the proliferation of in LPS-treated MSC via the PI3K/AKT pathway, while a lower concentration of PRP (1%) promoted MSC differentiation into osteoblasts through the MAPK pathway. Consistent with in vitro experiments, we validated the protective effect of PRP against LPS-induced bone loss by increasing bone formation in vivo. These results suggest that different concentrations of PRP can ameliorate LPS-induced inflammatory bone loss through distinct mechanisms.