Page 132 - IJB-9-5

International Journal of Bioprinting DLP-printed scaffold for bone regeneration

Figure 9. Histological evaluation of newly formed bone at week 4 and week 8. (A, C) Hematoxylin–eosin (HE) and (B, D) Masson’s trichrome (MASSON)
staining in the defect site at week 4. (E, G) HE and (F, H) MASSON staining in the defect site at week 8. (NB, new bone; HB, host bone; IM, implanted
materials; CB, chondrogenic bone.)

3D printing accuracy, but the good anti-swelling property examination, it was also found that some chondrocyte
also helps to better maintain the pore structure, and the aggregation was observed around the GelMA/3%PMAA
extended degradation time matches the rate of bone hydrogel, regardless of week 4 or week 8, with mineralized
regeneration (Figure 2). bone tissue appearing “in the surrounding” (Figure 9).
It was demonstrated that GelMA/3%PMAA scaffold
In vitro and in vivo bioeffects studies verified the
chelation iron ions in the material by ICP, Western blot, and could effectively promote chondrogenic differentiation of
BMSCs, which is vital for the induction of ECO.
PCR, and also confirmed that GelMA/3%PMAA promotes
the expression of HIF-1α as expected, which was crucial for Vascular regeneration is crucial for ECO, without
our next studies (Figure 4). As previously mentioned, two timely vascular invasion, and ECO will stagnate in
vital points for ECO are the chondrogenic differentiation the cartilage template and fail to mineralize into bone.
of BMSCs and the regeneration of blood vessels. After co- GelMA/3%PMAA played a non-negligible role in
cultured with GelMA/3%PMAA, the expression of SOX9 angiogenesis by promoting cartilage differentiation while
as well as the secretion of extracellular matrix components, also upregulating HIF-1α, promoting HUVECs migration
such as COL-II and ACAN, was improved, indicating the and VEGF expression (Figure 6). In addition, the
differentiation of BMSCs to cartilage. In contrast, only a histological staining showed that more blood vessels were
small amount of SOX9 expression was observed in GelMA formed in the GelMA/3%PMAA hydrogel group at week 4,
hydrogel (Figure 5). In combination with histological accompanied by more Osteopontin (OPN) expression.

Volume 9 Issue 5 (2023) 124 https://doi.org/10.18063/ijb.754