Modulatory effects of luteolin on osteoblastic function and inflammatory mediators in osteoblastic MC3T3-E1 cells

The effects of luteolin on the function of osteoblastic MC3T3-El cells and the production of local factors in osteoblasts were investigated. Luteolin (1 mu M) caused, a significant elevation of collagen content, alkaline phosphatase (ALP) activity, and osteocalcin secretion in the cells a (P < 0.05). The effect of luteolin in increasing collagen content and ALP activity was completely prevented by the presence of 10(-6) M cycloheximide and 10(-6) M tamoxifen, suggesting that luteolin's effect results from a newly synthesized protein component and might be partly involved in estrogen action. We then examined the effect of luteolin on the 3-morpholinosydnonimine (SIN-1)-induced production of oxidative stress markers [nitric oxide (NO) and prostaglan E-2 (PGE(2))] and cytokines [tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6)] in osteoblasts. Luteolin (1 and 10 mu M) decreased the SIN-1-induced production of NO, PGE(2), TNF-alpha, and IL-6 in osteoblasts. These results suggest that inflammatory mediators can be regulated by luteolin stimulating osteoblastic function. (C) 2007 International Federation for Cell Biology. Published by Elsevier Ltd. All rights reserved.