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Objective@# To investigate the effects of over expression and low expression of antisense transcripts of circular RNA cerebellar degeneration associated protein 1 (CDR1as) in Balb/C mouse bone marrow mesenchymal stem cells (BMSCs) on factors related to osteogenesis and angiogenesis.@*Methods@#BMSCs were cultured and identified in vitro. The lentiviral (LV) vector containing the overexpressed and silenced circRNA CDR1as genes and the control lentivirus were respectively transfected into mouse BMSCs, and stable cell lines were screened. The cells were divided into the circRNACDR1as over expression group and the over expression control group, and the CircRNACDR1as low expression group and the low expression control group. The components were stained with Alizarin Red S and alkaline phosphatase after 14 and 21 days of osteoinduction; qRT-PCR was used to detect the target genes circRNA CDR1as, osteogenic differentiation markers alkaline phosphatase (ALP), runt- related transcription factor 2 (RUNX2), osteocalcin (OCN), osteopontin (OPN), osterix(Osx), collagen I (COL-1), and the mRNA expression levels of vascular endothelial grown factor (VEGF) and angiogenin-1 (Ang-1). @*Results@# The results of alizarin red staining and alkaline phosphatase staining showed that the extracellular matrix calcium precipitation and ALP staining area of the over expression experimental group was greater than its control group, and those of the low expression experimental group was less than its control group. As the number of days of osteogenic induction increased, the calcium precipitation and ALP staining in each group also increased. RT-PCR results showed that the mRNA expression levels of circRNA CDR1as, ALP, RUNX2, OCN, OPN, OSX, COL-1, VEGF and Ang-1 in the over expression experimental group BMSCs were significantly increased (P<0.001). In the low expression experimental group, the mRNA expression levels of circRNA CDR1as, ALP, RUNX2, OCN, OPN, OSX, COL-1, VEGF and Ang-1 in BMSCs were significantly reduced (P<0.001). @*Conclusion@# Over expression of the circRNA CDR1as gene promotes the osteogenic differentiation and angiogenesis of BMSCs. Low expression of the circRNA CDR1as gene inhibits the osteogenic differentiation and angiogenesis of BMSCs.
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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.
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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.
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@# 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.
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Objective @# To study the distribution range of the color values of the upper anterior teeth of Uygur youth in the Kashi area of XinJiang as a reference for clinical applications.@*Methods@#Based on the International Commission on Illumination (CIE) L*a*b* color system, the colorimetric values of the anterior teeth of 212 Uygur youths in Xinjiang, Kashi, were analyzed by digital camera colorimetry. There were 105 males and 107 females. The length of the neck to the cutting end of the tooth was measured, and the tooth was evenly divided into thirds. To determine the chromaticity values of the incisors, lateral incisors, cuspids, and middle teeth, 1/3 of the cervical, middle and incisal regions and 9 test areas were measured. @*Results @#The color of the cervical, middle and incisal regions of the same tooth position in Uygur youth in the Kashi area showed the following trends: L* value: middle regions > cervical regions > incisal regions; a* value: cervical regions > incisal regions > middle regions; b* value: cervical regions > middle regions > incisal regions, and the differences were statistically significant (P < 0.05). The value of L* gradually decreased, and the value of a* gradually increased (P < 0.05). There were no significant differences in the a* value of male and female maxillary anterior teeth (P > 0.05). However, there was a significant difference in the b* value between the middle teeth and the incisors, the middle and the incisal regions of the upper maxillary incisors, and the cutting end of the upper maxillary incisors (P < 0.05). @*Conclusions @# There was a significant difference in the color of the cervical, middle and incisal of the same tooth. The upper jaw gradually reduced from the incisors to the sharp teeth, and the color gradually became reddish. The maxillary central incisor was brighter in males than in females, and the middle and incisal regions of the maxillary front teeth were more yellow than in males than in females.
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Objective@#o study the effect of cleaning treatment with hydrofluoric acid (HF) on the surface and bonding strength of IPS e.max and Vita Mark II ceramic inlays. @*Methods@#Fifty pieces of IPS e.max and Vita Mark II ceramic inlay specimens were made separately using CAD/CAM. After uniformly bonding surfaces using 9% HF etching, they were randomly divided into an untreated control group (group A) and the following experimental groups: neutralizing powder (B group), 37% phosphoric acid (group C), ultrasonic cleaning (group D) and neutralizing powder + 37% phosphoric acid + ultrasonic cleaning (group E). Each set of 8 specimens was bonded to Variolink N resin adhesive under standard conditions. The shear adhesive strength was measured after exposure to a constant-temperature water bath at 37 ℃ for 24 h. The location of the fracture and the type of adhesion failure were recorded. The shear adhesion and the average strength of the connection were analyzed. The remaining 2 specimens were used for scanning electron microscopy (SEM) to observe the surface morphology, including the crystal structure, pore pattern, and residue.@*Results @# The results were similar for the IPS e.max and Vita Mark II inlays. The maximum bond strength was observed in the IPS e.max ceramic inlays in group E, with an average bond strength 11.96 MPa higher than that in group A. Among the Vita Mark II porcelain inlays, the maximum bond strength was observed in group E. The average bond strength was 9.74 MPa higher than that in group A. The results of the statistical analysis were similar for the IPS e.max and Vita Mark II porcelain inlays, with significant differences in the bond strengths between groups C, D, and E and the control group (P < 0.05). There was no significant difference in the adhesive strength between groups B and A. At the same time, there was no significant difference in the bond strength between the treatment groups B, C, D, and E (P > 0.05). SEM revealed that the pores on the surface of ceramics subjected to the acid etching treatment were broadened and uniform, with less residue than observed in the control group. The effects of treatments D and E were the best. @*Conclusion@#The HF etching treatment can enhance the bonding strength of IPS e.max and Vita Mark Ⅱ ceramic inlays while leaving little residue, and the joint strength is highest when the joints are treated together.