Inhibition of Osteoclast Generation: A Novel Function of the Bone Morphogenetic Protein 7/Osteogenic Protein 1
Differentiation of CD14+ monocytes to osteoclasts in culture. (a) Monocytes were cultivated with RANKL (50 ng/mL) (●), RANKL, and OP-1 (1 g/mL) (■) or cultivated without stimulation (∘). In parallel, cells were cultivated for 7 days with RANKL, and then OP-1 was added (▲). At days 5, 7, 12, 17, and 22 the number of osteoclasts in relation to the total cell number was calculated (given are the mean values of triplicates with cells from one donor). (b) Monocytes of five individuals (each symbol stands for one individual) were cultivated with RANKL or with RANKL+OP-1 or left unstimulated with or without OP-1. After 22 days the percentage of osteoclasts was calculated (the mean values of the groups ± SD are given; the difference between the groups was calculated using -test for paired samples). (c) Monocytes were cultivated with either IL-8 (10 ng/mL; squares) or TNF (3 ng/mL) with (open symbols) or without (closed symbols) OP-1 and the percentage of osteoclasts was calculated at various times in culture (shown is the mean of duplicates and data of two individuals are shown).