Role of myeloid-derived suppressor cells in osteoclast differentiation in primary osteoporosis

• Myeloid-derived suppressor cells (MDSCs) exhibit stronger osteoclast differentiation potential than bone marrow-derived macrophages in vitro. • In naturally aged mice, the proportion of MDSCs in bone marrow increases, and their osteoclastogenic ability is enhanced, correlating with bone loss. • In ovariectomy-induced osteoporosis, MDSC proportion and serum inflammatory cytokines (TNF-α, IL-6) are elevated, and MDSCs show enhanced osteoclast differentiation. • MDSCs may contribute to primary osteoporosis by promoting osteoclastogenesis under aging and estrogen deficiency conditions.