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International Journal of Bioprinting DEX-Loaded PLGA microspheres enhance cartilage regeneration

Figure 4. Gross drawings of samples at days 3, 7, and 14 after bioink implantation in C57 mice.

both the GelMA control group and the PLGA-dex60 MPs@ 3.2.2. Evaluation of anti-inflammatory and
GelMA group, the capsules were significantly thicker (p < cartilage regeneration effects of DEX-loaded
0.0001). The PLGA-dex60 MPs@GelMA group exhibited PLGA microspheres
the thinnest capsules, with statistical differences compared In this study, we conducted a fusion approach combining
to all other groups except the GelMA control group. immunohistochemistry and RT-PCR to comprehensively

As illustrated in Figure 5A, the H&E staining results evaluate the anti-inflammatory effects and cartilage
revealed the formation of numerous chondrocyte-like regeneration capabilities of DEX-loaded PLGA
structures within the constructs of the PLGA-dex30 microspheres in a C57 mouse model.
MPs@GelMA group from day 7 onwards. The Alcian The immunohistochemical analysis was conducted
blue staining result in Figure 5B showcases the formation to investigate the effect of subcutaneous implantation on
of cartilaginous matrix in the regenerated cartilage macrophage polarization toward M1 (CD86+) phenotype
constructs from day 7 onwards, with matrix secretion at various time points. The PLGA-dex0 MPs@GelMA
increasing with the implantation time. By utilizing ImageJ group had the highest expression of CD86+ and exhibited
software, the average optical density (AOD) values of an increase in both the capsule thickness and CD86+ area
Alcian blue staining were calculated for the respective as the implantation progressed, as illustrated in Figure 6A.
groups. Remarkably, the PLGA-dex30 MPs@GelMA group Specific data from day 3 showed significant differences
exhibited statistically significant differences compared in AOD values between the PLGA-dex30 MPs@
to the other four groups (p < 0.0001). By the 14th day, GelMA group and both the GelMA control and PLGA-
through Alcian blue staining, visibly larger positive areas dex15 MPs@GelMA groups (p < 0.0001 and p < 0.05,
were observed in the PLGA-dex30 MPs@GelMA group, respectively), detailed further in Figure 6B–D. By day 7,
indicating enhanced cartilaginous matrix secretion. A there were significant differences between the PLGA-
series of statistical analyses revealed that the positive dex30 MPs@GelMA group and the PLGA-dex0 MPs@
staining area of PLGA-dex30 MPs@GelMA group was, in GelMA group (p < 0.0001), and no statistical difference was
general, significantly different compared to the other four found compared to the PLGA-dex15 MPs@GelMA group
groups (p < 0.0001).(Figure 5F–H). (p > 0.05). By day 14, capsule thickness analyses revealed

Volume 10 Issue 5 (2024) 392 doi: 10.36922/ijb.3396