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BACKGROUND: Akebia saponin D can promote the proliferation and differentiation of osteoblasts, increase the activity and quantity of osteoblasts, and promote matrix calcification and callus growth. Akebia saponin D is mainly used to treat osteoporosis and promote fracture healing, and its application in bone defect repair is rare. OBJECTIVE: To observe bone defects repaired by loading the sustained-release microspheres containing Akebia saponin D onto the nano hydroxyapatite/ chitosan scaffold. METHODS: The sustained-release microspheres containing Akebia saponin D were prepared by W/O/W method. The nano hydroxyapatite/chitosan scaffold of sustained-release microspheres containing Akebia saponin D (hereinafter referred to as the sustained-release scaffold) and the simple nano hydroxyapatite/ chitosan scaffold (hereinafter referred to as blank scaffold) were prepared by freeze drying method to evaluate the in vitro drug release ability of sustainedrelease microspheres and the scaffold. Mouse-derived preosteoblast MC3T3-E1 was seeded on two kinds of scaffolds to analyze cell adhesion, proliferation, and differentiation. Individually cultured cells were used as controls. A 1.5-cm bone defect was made in the middle of bilateral radius of 24 adult New Zealand white rabbits. Blank scaffold and sustained-release scaffold were implanted, separately. Gross observation, Micro-CT imaging examination, and histological observation were performed at 4 and 12 weeks after operation. RESULTS AND CONCLUSION: (1) Both the sustained-release microspheres and sustained-release scaffolds containing Akebia saponin D had sustained-release effects. The drug release rate of sustained-release scaffold was more stable and lasting. (2) CCK-8 assay demonstrated that the cell proliferation rate on the sustained-release scaffold was significantly faster than that on the blank scaffold and control groups (P < 0.05). Under the scanning electron microscope, mouse-derived preosteoblast MC3T3-E1 was covered on the scaffolds of the two groups, and the number of cells on the sustained-release scaffolds was more than that on the blank scaffolds. (3) At 7 and 14 days of culture, alkaline phosphatase activity and Runx2 mRNA expression were higher in the sustained-release scaffold group than those in the blank scaffold group (P < 0.05). At 21 days of culture, osteopontin and osteocalcin expression levels in the sustained-release scaffold group were higher than those in the blank scaffold group (P < 0.05). (4) The results of imaging and histological observation showed that at 4 weeks after operation, a large number of new bone were found around the materials in the sustained-release scaffold group, and the new bone mass was significantly higher than that of the blank scaffold group. At 12 weeks after operation, a large number of new bones grew in the sustained-release scaffold, while only a small amount of new bones was found in the blank scaffold, and the material residue in the sustained-release scaffold group was significantly lower than that of the blank scaffold group (P < 0.05). (5) These results verify that nano hydroxyapatite/chitosan scaffold of sustained-release microspheres containing Akebia saponin D can enhance the adhesion, proliferation, and differentiation of osteoblasts in vitro, and promote the osteoinductive ability of nano hydroxyapatite/ chitosan scaffold in vivo. [ABSTRACT FROM AUTHOR]

BACKGROUND: Hemostasis is an important part of clinical treatment. Fast and effective hemostasis is necessary to ensure the safety of surgical patients.OBJECTIVE: To prepare a kind of plant polysaccharide hemostatic microsphere with porous structure and its performance evaluation. METHODS: Porous hemostatic microspheres were prepared from potato starch by gelatinization, emulsification crosslinking, cleaning, and drying technique. The hemostatic performance of the hemostatic microspheres was improved by improving the gelatinization and crosslinking processes of the starches, setting the grouping: group A(gelatinization for 1 hour, crosslinking for 6 hours, group B（gelatinization for 1 hour, crosslinking for 12 hours）, group C（gelatinization for 1 hour, crosslinking for 18 hours）, group D（gelatinization for 2 hours, crosslinking for 6 hours）, group E（gelatinization for 2 hours, crosslinking for 12 hours）, and group F（gelatinization for 2 hours and crosslinking for 18 hours）. The listed absorbable hemostatic microspheres were used as controls to examine the microtopography, pH, porosity and in vitro degradation of microspheres in each group. According to the above experimental results, suitable microspheres were selected for hemostasis of liver and spleen in New Zealand rabbits, comparing the sample dosage, hemostasis amount with hemostasis time.RESULTS AND CONCLUSION:（1） Scanning electron microscope showed that group B and group E formed porous microspheres with a stable structure of 50-200 μm in diameter, and the spherical morphology and porosity were better than those of the control group. Except for groups C and E, the pH values of the other samples were in the range of 6.5-7.5, which met the pH requirements. The same quality of samples, the cross-linking time growth and degradation time increased significantly（P < 0.01）. Based on the examination of morphological structure, porosity, pH and in vitro degradation in the previous stage, groups A, B, E and the control group were selected for hemostasis experiments.（2） Under the same hemostatic effect, the hemostatic time of microspheres in group E was shorter and less used compared with that in the control group, and the hemostatic effect in group B was not significantly different from that in the control group.（3） The results showed that the porous starch microspheres prepared after gelatinization at 60 °C for 2 hours, emulsification for 45 minutes, and cross-linking for 12 hours had the best hemostatic effect and its degradation time was also relatively short, and its performance was superior to that of listed products. [ABSTRACT FROM AUTHOR]

BACKGROUND: Based on the need of in situ tissue engineering regeneration in the field of meniscus regeneration, three-dimensional (3D) bioprinting technology can be used to construct a scaffold which can effectively combine recruitment bioactive factors and excellent materials. OBJECTIVE: To optimize the preparation process of polycaprolactone/methacrylate anhydride gelatin/meniscus extracellular matrix (PCL/GelMA/MECM) 3D bioprinting scaffold loaded with platelets derived growth factor-BB (PDGF-BB), and to test the sustained release properties of the growth factor and its effect on the migration and proliferation of the synovial mesenchymal stem cells. METHODS: Photosensitive bio-ink was prepared by GelMA/MECM. PCL scaffold and PCL/GelMA/MECM bio-scaffold were prepared by 3D bioprinting technology. Finally, PDGF-BB was loaded to fabricate functional bioprinting PCL/GelMA/MECM/PDGF scaffold, and then its mechanical properties and sustained release properties were tested. New Zealand white rabbit synovial mesenchymal stem cells were isolated and cultured. Transwell and CCK-8 assays were used to explore the effects of PCL scaffold, PCL/GelMA/MECM scaffold and PCL/GelMA/MECM/PDGF scaffold on the migration and proliferation of synovial mesenchymal stem cells, and single medium cultured cells were used as negative control. The third passage of synovial mesenchymal stem cells was inoculated on PCL scaffold, PCL/GelMA/MECM scaffold and PCL/GelMA/MECM/PDGF scaffold respectively. The viability, adhesion and growth of the cells on the three scaffolds were observed by confocal microscope and scanning electron microscope. RESULTS AND CONCLUSION: (1) There was no significant difference in tensile modulus and compression modulus between PCL/GelMA/MECM scaffolds and PCL scaffolds (P > 0.05). (2) PCL/GelMA/MECM/PDGF scaffolds had good sustained release performance, and PDGF-BB could be released continuously for up to 28 days. (3) Compared with the negative control group, PCL/GelMA/MECM scaffolds and PCL/GelMA/MECM/PDGF scaffolds could promote the migration of synovial mesenchymal stem cells, among which PCL/GelMA/MECM/PDGF scaffolds were more effective. (4) Compared with the negative control group, the cells cultured with PCL/GelMA/MECM scaffolds and PCL/GelMA/MECM/PDGF scaffolds proliferated faster after 4 and 7 days (P < 0.001), and the proliferative effect of PCL/GelMA/MECM/PDGF scaffolds was more obvious. (5) Dead/Live staining showed that the cells in each group had good activity, and the number of cells on the PCL/GelMA/MECM/PDGF scaffold was the highest. (6) Scanning electron microscope showed that the cells were attached to the surface of the three groups of scaffolds, and the cells on PCL/GelMA/MECM scaffolds and PCL/GelMA/MECM/PDGF scaffolds adhered to a large number of cells and secreted a large amount of extracellular matrix. (7) These results showed that the 3D bioprinted meniscus scaffold loaded with PDGF-BB had good mechanical properties and biocompatibility and could promote the migration and proliferation of synovial mesenchymal stem cells. [ABSTRACT FROM AUTHOR]

BACKGROUND: Nanosized cell-type tissue-engineered bone is a good scaffold material possessing the merits of stem cells and nanomaterials to fabricate bone and soft tissue formation. OBJECTIVE: To explore the method of constructing nano-sized cell-type tissue-engineered bone and to explore its application in the repair of mandibular bone defects. METHODS: One New Zealand white rabbit was taken to isolate bone marrow stromal stem cells by centrifugation. Then, the cells were induced to differentiate into osteoblasts. Osteoblasts (3×108 /L, 10 μL) were inoculated into the prepared nano-phase hydroxyapatite/collagen composite to produce the nano-sized cell-type tissue-engineered bone. Another 20 New Zealand white rabbits were taken to make a unilateral puncture-type bone defect model of 15 mm×8 mm. These model rabbits were thereafter randomized into control and artificial bone groups (n=10 per group), followed by no intervention and implantation of nano-sized cell-type tissue-engineered bone, respectively. Repair effects were compared between the two groups. RESULTS AND CONCLUSION: (1) Under the inverted microscope, osteoblasts grew along the material in each group, and the number of cells increased with the prolongation of the culture time. (2) Under the scanning electron microscope, a large number of spindle- or polygon-shaped adherent cells grew well on the surface of the tissue-engineered bone. (3) The defect in the artificial bone group was lessened at 4 weeks after implantation and disappeared at 8 weeks after implantation, and there was no clear boundary with the surrounding tissue. In the control group, the defect size changed little at 4 weeks and reduced at 8 weeks after implantation, and a clear boundary with the surrounding tissue was observed. (4) Bone density, trabecular thickness and trabecular number were significantly higher in the artificial bone group than the control group at 4 and 8 weeks after implantation (P < 0.05). (5) At 4 weeks after implantation, many new bones at the defect site were detected in the artificial bone group, and a large number of mature bone cells were visible at 8 weeks. In the control group, a few osteoblasts were found at the defect site with low bone maturation at 4 and 8 weeks after implantation. These findings suggest that the implantation of nanosized cell-type tissue-engineered bone into the defect site can considerably promote defect healing and achieve ideal repair effects. [ABSTRACT FROM AUTHOR]