Optimizing

Background: Osteoclasts are multinucleated cells essential for bone resorption and remodeling. In healthy bone remodeling, osteoclast activity is tightly coupled with osteoblast activity, but this coupling is disrupted in a range of pathological conditions, such as Paget's disease of bone and delayed healing of fatigue fractures. Methods: In this study, we compared three methods for inducing osteoclast differentiation from mouse bone marrow-derived monocyte/macrophage (BMMs). Method 1 involved direct isolation of BMMs, Method 2 differentiated BMMs into bone marrow-derived macrophages (BMDM), and Method 3 incorporated Ficoll-Paque density gradient centrifugation prior to M-CSF-induced BMDM differentiation. For osteoclast differentiation, all three methods employed a complete medium containing 30 ng/mL M-CSF and 50 ng/mL RANKL. After first using TRAP staining, bone resorption assays, F-actin ring staining, quantitative reverse transcription polymerase chain reaction (RT-qPCR), and Western blot to identify the optimal plating density for each method, we then applied the same assays to compare osteoclastogenesis efficiency across the three methods at their optimal densities. Results: We found that Method 2, which involved differentiating BMMs into BMDM, yielded the highest proportion of live cells and osteoclast precursors, and exhibited the most efficient osteoclast differentiation. The optimal cell density for osteoclastogenesis was 2.8 ∼ 5.6 × 10 Conclusions: This study highlights the importance of precursor cell purity and seeding density in osteoclast differentiation. Method 2 (BMMs to BMDM) provides a simplified and effective approach for