Inhibits Multinucleated Osteoclast Formation and Prevents Estrogen-Deficient Osteoporosis.

Mollusks have served as important sources of human food and medicine for a long time. Raw , a freshwater bivalve of the phylum Mollusca, is used in traditional therapies in parts of Asia. However, the therapeutic effects of on bone diseases are not known. We investigated the functional roles of in osteoporotic bone diseases. inhibited the differentiation of bone marrow-derived monocytic cells into mature osteoclasts in vitro. The ovariectomized mice that received oral administration of showed improvements in both trabecular and cortical bones. This preventive activity of against bone loss was due to limited osteoclast maturation with reduced osteoclast surface extent in trabecular bone tissue. The formation of large multinucleated osteoclasts in vitro was significantly decreased in response to , consistent with the reduced expression levels of osteoclast markers and fusion-related genes, such as , , , -, , , , , and . These data suggest that inhibits osteoclast differentiation by negatively regulating the fusion of mononuclear osteoclast precursors. Thus, our data demonstrate the ability of to effectively prevent estrogen-deficient osteoporosis through inhibition of multinucleated osteoclast formation.