ABSTRACT
BACKGROUND:There are several reports about the application of fresh bone marrow aspirate being injected directly to repair partial ligament injury, but the application about fresh bone marrow aspirate directly being planted on scaffolds to build tissue-engineered ligament is rarely mentioned. OBJECTIVE:To evaluate the feasibility of applying fresh bone marrow aspirate planted directly on scaffolds to construct tissue-engineered ligament METHODS:We constructed fibroin fiber/smal intestinal submucosa composite scaffold, then planting fresh bone marrow directly to built bone marrow seeding group and planting seed cel s (bone marrow mesenchymal stem cel s) on the scaffold to built cel seeding group. The control group had no treatment. After that, we detected the density of cel adhesion, cel proliferation ability and extracel ular matrix secretion. Then, the composite in the bone marrow seeding group was implanted into the broken anterior cruciate ligament in rabbits, and material biocompatibility in vivo was evaluated after 12 weeks. RESULTS AND CONCLUSION:After 4 hours of incubation, bone marrow seeding group was significantly higher than the cel seeding group in cel adhesion density and proliferation rate (P<0.05). Bone marrow seeding group and cel seeding group showed higher type I, III col agen secretion compared with the control group (P<0.05), but the col agen secretion of bone marrow seeding group and cel seeding group showed no significant difference. Composite cel scaffold implantation in vivo did not cause fatal immune rejection and severe inflammatory reaction, and no significant ligament regeneration and vascularization occurred. These findings indicate that fresh bone marrow aspirate can be seeded directly on scaffolds to construct tissue-engineered ligament, and the short-term biocompatibility in vivo is good.
ABSTRACT
In order to investigate the effect of Arg-Gly-Asp (RGD) peptide-modified silk biomaterial on the adhesion and proliferation of bone marrow-derived mesenchymal stem cells (MSCs), MSCs of third generation were seeded onto the surface of RGD-decorated silk (silk-RGD group), silk alone (silk group) or tissue culture plate (TCP group). After incubation for 4 or 12 h, MSCs were examined quantitatively by using precipitation method for cell attachment. The cell proliferation, which was defined as cell density, was compared among the three groups after culture for 1, 2, 3, and 4 days. Cell skeleton, which was labeled fluorescently, was observed under laser confocal microscope after 24 h of culture. The results showed that cell adhesion rate in silk-RGD group was higher than in silk group (P0.05). There were no significant differences in the cell proliferation among the three groups at different time points (P>0.05 for all). Laser confocal microscopy revealed that in silk-RGD group, MSCs, strongly fluorescently stained, spread fully, with stress fibers clearly seen, while in silk group, actin filaments were sparsely aligned and less stress fibers were found. It was concluded that RGD peptide could improve the adhesion of MSCs to the silk scaffold, but had no impact on the proliferation of the cells.
Subject(s)
Biocompatible Materials/chemistry , Bone Marrow Cells/cytology , Cell Adhesion/drug effects , Cell Proliferation/drug effects , Mesenchymal Stem Cells/cytology , Oligopeptides/chemistry , Silk/chemistry , Tissue ScaffoldsABSTRACT
BACKGROUND: Presently, the biomaterial used in ligament tissue engineering such as collagen protein, polylactic acid, polyglycolic acid, small intestinal submucosa, glycan and nanomaterial are characterized by rapid degradation, resulting in inflammatory reaction after applying in host.OBJECTIVE: To investigate mechanical strength and in vitro degradation of silk scaffold and explore the reaction to macrophages.DESIGN: Controlled experiment.SETTING: Experiments were performed at the Department of Orthopaedics, Union Hospital, Huazhong University of Science and Technology from September 2004 to January 2005.MATERIALS: White raw Bombyx mori silkworm fibers of size 20/22 (according to the manufacturer) were obtained from the market. Bundles of 30 parallel fibers were prepared for a bundle of scaffold, which was put into fervens 5g/L Na2CO3for degumming. Ratio of Na2CO3 solution (Ml) to raw silk (g) was 1000.METHODS: In vitro degradation: 8cm long silk scaffold was weighed after drying. Subsequently, the silk scaffold was separately dipped into phosphate buffer saline (PBS) and 1.0g/L collagenase prepared with PBS. Twelve weeks later, silk scaffold was weighed to calculate weight loss rate. Simultaneously, tensile test was performed to detect the ultimate tensile strength (UTS) of samples. Culture of monocyte strain RAW264.7:2×108L-1 macrophage suspension (1mL) were separately added in a silk scaffold group, a control group and a lipopolysaccharide (LPS) group. At days 1 and 7, cell supernatant was collected from each group. Tumor necrosis factor-α(TNF-α) levels were measured by enzyme linked immunosorbent assay (ELISA).MAIN OUTCOME MEASURES: ① Changes in weight loss rate and UTS of the silk matrices after incubated with collagenase and the PBS. ②TNF-αlevels in the supernatant of each groups at days 1 and 7.RESULTS: Mass of silk matrices reduced by over 50% after incubated with collagenase for 8 weeks, but no change was found in PBS. UTS decreased by over 50% 8 weeks after incubated with collagenase, but no change was detected in PBS. At days 1 and 7, TNF-α levels in the supernatant was less in the silk scaffold group; TNF-α levels in the supernatant was significantly higher in the LPS group than in the silk scaffold group (P<0.01), but no significant difference in TNF-α levels was measured between the silk scaffold group and the control group (P>0.05).CONCLUSION: After 12-weeks degradation, silk scaffold still has good mechanical properties. Macrophages possess immunological inertia at days 1 and 7 after inoculated with macrophages.
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0.05), and the total score were similar in the two groups. Type Ⅱ collagen in the two groups was strongly positive by immunohistochemistry staining. CONCLUSION: Cryopreserved allogenic osteochondral pillars transplantation can repair small full-thickness articular cartilage defects. The chondrocytes are alive in short time, and they can secret cartilage matrix without obvious rejection. It has similar efficacy in histology with autogenic osteochondral pillar transplantation.
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0.05).CONCLUSION:The excellent mechanical properties of composite ligament can meet the mechanical requirements of appropriate ligament tissue engineering scaffolds.