Figure 6. The effects of BMP-7 stimulation on mono- and cocultures of primary bovine osteoblasts and fibroblasts, combining the following 6 experimental groups: monoculture pOBs without BMP-7 (pOB-BMP); monoculture pOBs with 400 ng/ml BMP-7 (pOB+BMP); monoculture pFBs without BMP-7 (pFB-BMP); monoculture pFBs with 400 ng/ml BMP-7 (pFB+BMP); coculture pOBs and pFBs without BMP-7 (pOB+pFB-BMP); and coculture pOBs and pFBs with 400 ng/ml BMP-7 (pOB+pFB+BMP).

(A) The BMP-7 application significantly increased the ALP activity in the pFB and pOB monocultures from day 20, whereas no significant effects were found in the coculture groups. (B) Stimulation with BMP-7 led to a significant increase in the cellular ALP activity in the pOB monocultures and cocultures. At the end of the experiment, a significant increase in cellular ALP activity was detectable following BMP-7 stimulation in the fibroblast monoculture. (C) The lactate concentration significantly increased in all groups following a delay of 12 to 16 days after BMP-7 stimulation. At the end, a decrease or an inversion of the effect of BMP-7 was found. (D) BMP-7 application resulted in significantly increased LDH activity in the pFB monoculture. At day 20, the stimulated groups showed significantly higher LDH activity. The data are presented as mean ± standard deviation. The asterisks (*) indicate the significant differences between the stimulated and the non-stimulated groups (*p<0.05, **p<0.01, ***p<0.001).