Application of biomimetic three-dimensional scaffolds in bone tissue repairing

Efficacy of Three-Dimensional Bioactive Composites in Long Bone Repair with Photobiomodulation

Different treatments have been proposed for morphofunctional bone repair; however, they are not always efficient and have limitations. In this experimental study, we present matrix composites with a possible synergistic effect acting with scaffolds for bone growth and use of photobiomodulation (PBM) to accelerate this tissue repair. Thus, the objective was to evaluate the effect of PBM in the repair of a long bone (tibia) of rats filled with biomimetic collagen matrices with nanohydroxyapatite and heterologous fibrin biopolymer (FB). Forty-eight rats were distributed into eight groups (n = six each): Blood Clot (BC), Blood Clot + PBM (BCP), Matrix (M), Matrix + PBM (MP), Fibrin Biopolymer (FB), Fibrin Biopolymer + PBM (FBP), Matrix + FB (MFB), Matrix + FB + PBM (MFBP). A 2.0 mm bone defect was created in the proximal third of the left tibia. The BCP, MP, FBP, and MFBP groups underwent PBM during surgery and maintained twice a week until euthanasia at 42 days. Microcomputed tomography (micro-CT), histomorphological and histomorphometric analyses were performed. Micro-CT analysis revealed that PBM influenced cortical interposition between the remnant and newly formed bone. Histologically, no exacerbated inflammatory focus or foreign body-type granulomatous reaction was observed in any group; however, a vast collagenous matrix with a more oriented and thicker spatial conformation was observed in the PBM-treated groups. Histomorphometrically, the BCP, MP, and MFBP groups showed significantly higher values compared to the other groups. Specifically, the BC group presented a mean bone tissue density of 68.33 ± 7.394, while the BCP and MP groups showed 99.83 ± 11.87 and 99.67 ± 20.58, respectively (p < 0.05). Qualitative analysis of collagen fibers indicated enhanced organization and maturation in PBM-treated groups. This study concluded that the association of PBM in the repair of long bones in rats, filled with biomimetic collagen matrices with nanohydroxyapatite and fibrin biopolymer, presented results that contribute to the improvement of bone growth, together with the association of scaffolds.

Dihydromyricetin-loaded oxidized polysaccharide/L-arginine chitosan adhesive hydrogel promotes bone regeneration by regulating PI3K/AKT signaling pathway and MAPK signaling pathway

Bone defects caused by trauma, infection and congenital diseases still face great challenges. Dihydromyricetin (DHM) is a kind of flavone extracted from Ampelopsis grossedentata, a traditional Chinese medicine. DHM can enhance the osteogenic differentiation of human bone marrow mesenchymal stem cells with the potential to promote bone regeneration. Hydrogel can be used as a carrier of DHM to promote bone regeneration due to its unique biochemical characteristics and three-dimensional structure. In this study, oxidized phellinus igniarius polysaccharides (OP) and L-arginine chitosan (CA) are used to develop hydrogel. The pore size and gel strength of the hydrogel can be changed by adjusting the oxidation degree of oxidized phellinus igniarius polysaccharides. The addition of DHM further reduce the pore size of the hydrogel (213 μm), increase the mechanical properties of the hydrogel, and increase the antioxidant and antibacterial activities of the hydrogel. The scavenging rate of DPPH are 72.30 ± 0.33 %, and the inhibition rate of E.coli and S.aureus are 93.12 ± 0.38 % and 94.49 ± 1.57 %, respectively. In addition, PCAD has good adhesion and biocompatibility, and its extract can effectively promote the osteogenic differentiation of MC3T3-E1 cells. Network pharmacology and molecular docking show that the promoting effect of DHM on osteogenesis may be achieved by activating the PI3K/AKT and MAPK signaling pathways. This is confirmed through in vitro cell experiments and in vivo animal experiments.