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International Journal of Bioprinting 3D-printed Mg scaffolds promote bone defect repair

Figure 5. Reactive oxygen species (ROS) levels and the expression of osteoclast differentiation genes in BMMs cultured in the extract of naked JDBM (Mg),
Mg/Sc, and Mg/Sc/ZA samples and stimulated with RANKL (100 ng/mL) for 5 days. (A) Representative images of ROS in BMMs cells under fluorescence
microscope for 48 h. (B) Quantitative ROS fluorescence intensity. (C) Relative expression of osteoclast-specific genes. *P < 0.05 vs. Control group;
# P < 0.05 vs. Mg group.

of TRAP-positive osteoclasts in the control group were the average number of F-actin rings in the Mg and Mg/Sc/
significantly higher than those in the other three groups. ZA groups was significantly lower than that in the control
The number and area of TRAP-positive osteoclasts in the group (Figure 4D). As shown in Figure 4E, the bone
Mg group were lowest, whereas those in the Mg/Sc group resorption area of Mg group is negligible and the area of
were relatively large (Figure 4B). The reason for the small bone resorption area is the smallest. Quantitative analysis
number and area of osteoclasts in the Mg group was that the of the resorption area showed that the bone resorption area
environment formed by the rapid degradation of the Mg in the Mg, Mg/Sc, and Mg/Sc/ZA groups was significantly
alloy in the Mg group was disadvantageous for the growth lower than that in the control group, and there was a
and differentiation of osteoclasts. A comparison of staining significant difference between the Mg and Mg/Sc groups
results between the Mg/Sc and Mg/Sc/ZA groups showed (Figure 4F). It can be concluded that extracts of the coating
that ZA released by the Mg alloy coating in the Mg/Sc/ZA samples of the Mg/Sc/ZA group significantly inhibited
group effectively inhibited osteoclast differentiation and osteoclast bone resorption through the slow release
hindered osteoclast formation and further differentiation. of ZA. In addition, the expression levels of osteoclast
The inhibitory effect of the Mg/Sc/ZA scaffold extracts differentiation-related genes, such as c-Fos, Acp5, Ctsk,
on osteoclast differentiation was confirmed by staining NFATc1, Calcr, and MMP9, were significantly lower than
osteoclast actin rings with rhodamine-conjugated those in the control group (Figure 5C). From the results of
phalloidin (Figure 4C). Quantitative analysis revealed that the detection and quantitative analysis, it was found that

Volume 9 Issue 5 (2023) 410 https://doi.org/10.18063/ijb.769