Soybean ethanol extract increases the function of osteoblastic MC3T3-E1 cells

To investigate the bioactivities of soybean, which act on bone metabolism, we studied the effect of a soybean ethanol extract on the activity of osteo blast MC3T3-E1 cells. Soy extract (0.01-0.1 g/l) dose-dependently increased survival (P<0.05) and DNA synthesis (P < 0.05) of MC3T3-E1 cells. In addit ion, soy extract (0.05 g/l) increased alkaline phosphatase activity (P < 0. 05) and collagen synthesis (P < 0.05) of MC3T3-E1 cells. Moreover, the anti -estrogen tamoxifen eliminated the stimulation of MC3T3-E1 cells on the pro liferation, ALP activity and collagen synthesis by soy extract, indicating that the main action of the soy extract on osteoblastic MC3T3-E1 cells is s imilar to that of estrogen effects. Treatment with soy extract prevented ap optosis, as assessed by a one-step sandwich immunoassay and DNA gel electro phoresis studies. This effect may be associated with the activation of the estrogen receptor, since we observed soy extract-mediated survival against apoptosis was blocked by the estrogen receptor antagonist tamoxifen in cell s, further supporting a receptor-mediated mechanism of cell survival. These results suggest that osteoblast function is promoted by soy extract and th at the estrogen receptor is involved in the response, thereby playing an im portant role in bone remodeling. In conclusion, soy extract has a direct st imulatory effect on bone formation in cultured osteoblastic cell in vitro. Presumably, dietary soy products are useful in the prevention of osteoporos is. (C) 2001 Elsevier Science Ltd. AII rights reserved.