ABSTRACT
Objective@#To investigate the level of hypoxia inducible factor-1α (HIF-1α) on osteoblasts and angiogenesis-associated cytokines in bone marrow mesenchymal stem cells (BMSCs) from SD rats.@*Methods@#BMSCs were isolated and cultured and identified by flow cytometry. Plasmid vectors containing upregulated and downregulated HIF-1α gene and a control vector were constructed. The plasmids were transfected into BMSCs by Lipofectamine®LTX transfection reagent, and the cells were divided into an overexpression experimental group, an overexpression control group, a low expression experimental group and a low expression control group. All components were stained with a lizarin red 3 d and 7 d after osteogenesis induction. The mRNA expression levels of the target gene HIF-1α, osteogenic differentiation-specific markers, including Runt-related transcription factor 2 (Runx2) and angiogenic markers, including platelet-derived growth factor-BB (PDGF-BB) and transforming growth factor-β (TGF-β), were detected by RT-PCR. Western blot was used to detect the protein expression of the target proteins HIF-1α, Runx2, and PDGF-BB.@*Results@# The CD29- and CD45-positivity rates of BMSC surface markers identified by flow cytometry were 98.2% and 4.2%, respectively. RT-PCR results showed that the mRNA expression of HIF-1α, Runx2, TGF-β and PDGF-BB was observably increased (P < 0.001). The mRNA expression levels of HIF-1α, Runx2, TGF-β and PDGF-BB in BMSCs from the low expression experimental group were significantly reduced (P < 0.001). Western blot results showed that the expression levels of HIF-1α, Runx2 and PDGF-BB in BMSCs from the overexpression experimental group were all increased (P < 0.001). The expression levels of HIF-1α, Runx2 and PDGF-BB in BMSCs from the low expression experimental group were reduced (P < 0.001). Alizarin red staining results showed that the area of calcium nodules in the low expression experimental group was smaller than that in low expression control group, the area of red calcium nodules in the over expression experimental group was larger than that in over expression control group, and with the increase of osteogenic induction time, the calcification area of each group also increased.@*Conclusion@# Upregulation and downregulation of HIF-1α can regulate the osteogenic differentiation and the expression of angiogenesis related factors of BMSCs.
ABSTRACT
Objective @#To explore the feasibility of antler powder/silk fibroin/polyvinyl alcohol scaffolds as tissue engineering bone scaffolds and the relationship between their degradation performance and the healing speed of bone defects.@*Methods @# Antler powder/silk fibroin/polyvinyl alcohol scaffolds and nano hydroxyapatite/silk fibroin/polyvinyl alcohol scaffolds were prepared by 3D printing. The whole bone marrow culture method was used to prepare blood cell sheets of Altay big tail sheep’s iliac bone marrow. With observation times of 1, 2 and 3 months, the mandibular defects of 4 sheep were established. The experimental group was coated with antler powder/silk fibroin/polyvinyl alcohol scaffolds. The control group was coated with nanohydroxyapatite/silk fibroin/polyvinyl alcohol scaffolds. The negative control group was coated with gel-free sponges. According to the self-control method of the bilateral mandible defect area, scaffolds wrapped with cell membranes or gel sponges wrapped with cell membranes were implanted. At the ends of the first, second and third months after implantation, the experimental animals were killed, cone beam CT was performed, and paraffin sections were taken for HE staining to evaluate the effect of different scaffold materials on bone regeneration and scaffold degradation.@* Results@# Scanning electron microscopy showed that both groups had regular pores and good continuity, and there was no difference in pore size and porosity between the two groups (P > 0.05). The results of CBCT imaging showed that in 3 months after operation, the experimental group had significantly better repair effects on bone defects than the control group, and the degradation rate matched the bone repair rate. The bone mineral density in the center of the defect was higher than that of the control group, which was close to that of normal bone tissue. The central bone mineral density of the experimental group at each time point was higher than those of the control group and the negative control group, and the difference was statistically significant (P < 0.05). HE staining results showed that the bone cells in the experimental group were more active, with more new capillaries and bone trabeculae formed, and the scaffold material absorbed more than the control group. @*Conclusion @#The antler powder/silk fibroin/polyvinyl alcohol scaffold can promote the repair of critical bone defects. Its degradability matches its bone tissue healing rate. It is expected to become a promising scaffold material for bone tissue engineering.
ABSTRACT
@# Three dimensionally printed composite porous bone tissue engineering scaffolds have become a research focus. Composite polyvinyl alcohol (PVA) has good biocompatibilityand degradability, but it cannot be prepared indepen⁃dently because it cannot resist highmechanical resistance. This material shows many advantages, such as good biocom⁃patibility, degradability and mechanical properties, when compounded with other materials with good mechanical proper⁃ties and good biocompatibility. Therefore, 3D printed composite PVA scaffold material can optimize the performance of PVA scaffolds. This article reviews 3D printing bone scaffold technology, polyvinyl alcohol (PVA), and composite PVA scaffolds for in vivo and in vitro bone formation.