Figure 7.

Osteogenic differentiation after 14 days under the influence of conditioned medium from immune cells. (A) 3 months old mesenchymal stromal cells (MSC) were compared to 12 months old MSC. The 12 months old MSC showed a reduced osteogenic differentiation potential compared to 3 months old MSC. Adding conditioned medium from immune cells (conditioning for 48 h) that were not activated did not affect the osteogenic differentiation, but adding conditioned medium from activated immune cells lowered the differentiation potential. The conditioned medium from 12 months old mice worsened the ability to differentiate into the osteogenic lineage. (B) Representative images of the calcium deposition stained by Alizarin Red S comparing 3 and 12 months old MSC under the influence of different conditioned medium. Twelve months old MSC under the influence of activated 12 months old conditioned medium almost abolished the ability for calcium deposition. (C) Analysis of the conditioned medium showed an increase of pro- (IFNγ and TNFα) and anti-inflammatory (IL-10) cytokines from 12 months old immune cells. N = 6 animals per age, conditioned medium was pooled and added at a ratio of 1:3 to the osteogenic differentiation medium, assays were performed in triplicates, mean ± SD, unpaired t-test, ^*p < 0.05.