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Söhling, et al.
A B

C D

Figure 7. MSCs immune response to PLA/BG composites. Gene expression of inflammatory markers MAPK-8, MAPK-14, and IL-6 as well
as protein expression of IL-6 were measured in the cells/supernatant cultured in the presence of different BG concentrations (n=5). (A) With
increasing BG content, there is a decrease in IL-6 gene expression. For PLA/BG 10%, IL-6 gene expression after 24 h significantly decreases
compared to PLA/BG10% after 72 h and 168 h. (B) No inhibition of IL-6 release by BG was observed. IL-6 levels remain relatively constant
regardless of BG content and time period. (C) A significant decrease in MAPK-8 gene expression is also evident for cells cultured in contact
with PLA/BG 10% and PLA/BG 20%. (D) For MAPK-14, an increase in expression can be detected at a BG content of 5% after 72 h and
168 h.

The present study shows the OD of MSC under the
influence of BG.
The MSC gene expression profile shows a
characteristic course during the different phases of OD.
In this experiment, the focus was on the early phase of
OD up to day 7. For this phase, a significant increase in
the ALP gene expression was proven . This is in line
[46]
with our experimental outcomes. For MSCs cultured in
standard medium on BG20, a significant increase in ALP
gene expression was measured at day 7 compared to the
PLA control.
Figure 8. Gene expression of IL-6 (A) in MSC cultivated 72 h in As an essential transcription factor for OD, RUNX2
[47]
the presence of BG20 is dependent on calcium ions released by is expressed in the early phase after induction of OD .
the BG content. Calcium ions were chelated by presence of EGTA Here, RUNX2 gene expression was increased when the
modifying relative mRNA expression of IL-6 in MSC cultured cells were cultured on BG10 and BG20, albeit without
with BG20 (n=3). *Shows P<0.05 versus indicated group. Results statistical significance compared to PLA control.
are mean values of the three measurements and their standard Significant decrease of RUNX2 gene expression in MSC
deviation.
cultivated on BG20 has been shown after 72 h and 168 h.
The rapid decline of RUNX-2 expression as one initial step
material of BG (G5 glass) and PLA enhanced the of OD in MSC is also congruent with previously reported
differentiation of EPC and their angiogenic activity . work on osteogenic MSC differentiation . Nevertheless,
[35]
[45]
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