eng Science and Education Publishing Journal of Food and Nutrition Research 2333-1240 2016-07-14 4 7 429 435 10.12691/jfnr-4-7-3 JFNR2016473 article Shinichi Katsumata s1katsum@nodai.ac.jp 1 2 Gabrielle G. Plimmer 2 Miki Tadaishi 2 3 Yuko Tousen 3 Yoshiko Ishimi 3 Marlena C. Kruger 3 Institute of Food, Nutrition and Human Health, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand Soy isoflavones and docosahexaenoic acid (DHA) are effective for maintaining bone health. This study investigated the combined effects of soy isoflavones and DHA on osteoclast formation. Mouse bone marrow cells were pre-cultured with macrophage colony-stimulating factor (M-CSF) for 3 days and then cultured with M-CSF and receptor activator of nuclear factor κB ligand (RANKL) for 6 days. RAW 264.7 cells were cultured with RANKL for 5 days. In mouse bone marrow cells, daidzein, genistein, and DHA significantly decreased the number of tartrate-resistant acid phosphatase-positive multinucleated cells (TRAP(+)MNCs), and the combination of soy isoflavones and DHA further decreased the number of TRAP(+)MNCs. Nuclear factor of activated T-cells c1 (NFATc1) mRNA expression tended to be decreased by daidzein, and was significantly decreased by genistein and DHA. Furthermore, the combination of daidzein and DHA caused significant reduction in NFATc1 mRNA expression compared to the control. In RAW 264.7 cells, daidzein tended to decrease and genistein significantly decreased the number of TRAP(+)MNCs, however, the combination of daidzein and DHA significantly decreased the number of TRAP(+)MNCs compared to the control. These results demonstrated that the combination of soy isoflavones and DHA decreased in osteoclast formation significantly, possibly by modulating the expression of specific genes. http://pubs.sciepub.com/jfnr/4/7/3/jfnr-4-7-3.pdf soy isoflavones docosahexaenoic acid osteoclast formation mouse bone marrow cells RAW 2647 cells