Synergic effects of decellularized bone matrix, hydroxyapatite, and extracellular vesicles on repairing of the rabbit mandibular bone defect model

Abstract

Background Extracellular vesicles (ECV) have beneficial effects on the treatment of some pathological cases such as bone defects. Besides, the bone extracellular matrix (ECM) has been used to restore bone damage. Since major bone defects showed low spontaneous repairing ability, the purpose of this study was to find the synergic effect of decellularized bone (DB) ECM and ECVs on the repair of rabbit z. Methods The quality of decellularized sheep bones was confirmed by H&E, Hoechst, and DNA quantification. Also, immunohistochemistry, histochemical staining, and scanning electron microscopy (SEM) were done to evaluate the retaining of ECM constitutions. Osteoblast-derived ECVs were evaluated by internalization test, Transmission electron microscopy, Dynamic light scattering, and flow cytometry for CD9, CD63, CD81 markers. The hydrogel containing DB and hydroxyapatite (HA) with or without ECVs was evaluated for osteoblast functions and bone repair both in vitro and in vivo. Results SEM, histochemistry, DNA quantification, and immunohistochemistry indicated that the ECM was preserved after decellularization, while the cell and nuclear debris were removed sufficiently. In vitro assessments revealed that mineralization and alkaline phosphatase activity did not improve after treatment of MG63 cells by ECVs, while in vivo assessments showed synergic effects of ECVs and DB+HA hydrogels compared to the control, DB+HA and ECV-treated groups. Morphometric estimations revealed that the number of the bone-specific cells and vessel and bone area increased in bone defect treated with DB+HA/ECVs. Conclusion The DB enriched with ECVs can be an ideal scaffold for bone tissue engineering and may provide a suitable niche for migration and differentiation of the bone cells.

Bioactive composite hydrogels as 3D mesenchymal stem cell encapsulation environment for bone tissue engineering: in vitro and in vivo studies

“…While the amount of DNA in native cancellous bone was 82.653 ± 1.071 ng mg −1 tissue, this value was determined as 27.963 ± 2.087 ng mg −1 tissue in decellularized cancellous bone tissue (Figure 2B). DNA content analysis findings revealed a value below the generally accepted 50 ng DNA mg −1 tissue limit for decellularized tissues 47 . As is known, this low DNA level in decellularized tissue grafts can promote tissue regeneration in vivo while inducing a mild, tolerable immune response 27,28 …”

“…Percent collagen contents of native and decellularized cancellous bone tissue are given in Figure 2D, and measured at the levels of 278. 47 tissue is maintained at a rate of $57% after the application of the decellularization protocol. Collagen has binding sites suitable for cell interaction and can be considered as a biological structural element for the adhesion, proliferation and differentiation of cells.…”

“…DNA content analysis findings revealed a value below the generally accepted 50 ng DNA mg À1 tissue limit for decellularized tissues. 47 As is known, this low DNA level in decellularized tissue grafts can promote tissue regeneration in vivo while inducing a mild, tolerable immune response. 27,28 Results of the sGAG content analysis of native and decellularized cancellous bone tissue are given in Figure 2C.…”