A previous animal study conducted in our lab showed that blueberry, a rich source of polyphenols, was able to increase whole-body BMD in ovariectomized (OVX) rat model. In addition, blueberry, as low as 5% in the diet, was able to suppress ovariectomy-induced rate of bone turnover. The present study was conducted to further investigate the anti-inflammatory properties of blueberry total polyphenols in MC3T3-E1 preosteoblast cells treated with tumor necrosis factor- and #945; (TNF- and #945;) and interleukin 1 (IL-1) on a molecular level. Cells were treated with blueberry (0, 10, 100 and #956;g/ml) for 24 h prior to the treatment of TNF- and #945; (10 ng/ml) or IL-1 (10 ng/ml) or combination of these two cytokines for 24 h and 48 h. Cell viability, nitric oxide (NO) production and expression of osteoclastogenesis and osteoblastogenesis factors mRNA were measured. The findings indicated that blueberry failed to significantly increase cell proliferation in the presence of proinflammatory cytokines, but blueberry polyphenols were able to significantly suppress NO production stimulated by either TNF- and #945; or IL-1. There was no inhibitory effect of blueberry on NO production in the presence of both TNF- and #945; and IL-1. On the molecular level, 10 and #956;g/ml of blueberry decreased osteoclastogenesis mediators, such as TNF- and #945;, TNF- and #945; receptor (TNFR), TNF- and #945; receptor associated factor (TRAF), macrophages-colony stimulating factor (M-CSF), receptor activator of nuclear factor and #954;B ligand (RANKL), IL-1, interleukin 6 (IL-6), and inducible NO synthase (NOS2) numerically but not significantly. However, blueberry promoted expression of osteoblastogenesis mRNA, such as osteoprotegerin (OPG), runt-related transcription factor 2 (RUNX2), and osterix (OSX), under the inflammatory condition induced by cytokine mixture. In conclusion, blueberry polyphenols significantly suppressed NO production, were beneficial for up regulating transcriptions of factors that promote MC3T3-E1 preosteoblasts formation and activation. However, blueberry did not have inhibitory effects on production of osteoclastogenesis mediators under inflammatory conditions.
