ObjectiveTo observe the morphological characteristic by implanting domestic porous tantalum in rabbit patellar tendon and to evaluate biocompatibility features so as to provide experimental basis for porous tantalum used as interface fixation between tendon and bone.
MethodsA total of 48 adult New Zealand white rabbits, male or female, weighing 2.5-3.0 kg, were selected. Porous tantalum flake (5 mm×5 mm×2 mm) was implanted in the left patellar tendon (experimental group) and the same size porous titanium flake in the right patellar tendon (control group). The animals were sacrificed at 2, 4, 8, and 12 weeks after implantation, then the specimens were harvested for gross observation, HE staining, scanning electron microscope (SEM) observation, and hard slices observation.
ResultsNo animal died after operation. Porous tantalum was bonded closely with host tendon and no inflammatory reaction was found. Loose and thick fibrous capsule was observed at the beginning and became density and thinner in the end by microscope, showing significant difference between different time points in 2 groups (P<0.05), but no significant difference was found between 2 groups at different time points (P>0.05). The SEM observation showed that fibrous tissue attached to the surface and inner walls of porous tantalum at early stage, and extended on the material to reach confluence at late period, but the experimental group was more than the control group. Hard slices observation showed that the collagen fibrils were seen on porous tantalum interface with host tendon, and blood vessels grew into the pores. The control group and the experimental group showed no significant difference.
ConclusionThe domestic porous tantalum has good biocompatibility. Connection and integration can be established between tendon and porous tantalum, and therefore it could be used in reconstruction of tendon-bone fixation device.
ObjectiveTo summarize the research progress of tissue-engineered bile duct in recent years.
MethodsThe related literatures about the tissue-engineered bile duct were reviewed.
ResultsIn recent years, the research of tissue-engineered bile duct has made a breakthrough in scaffold materials, seed cells, growth factors etc. However, the tissue-engineered bile duct is still in the research stage of animal experiments, which can not be directly applied to clinical practice.
ConclusionsThe research of tissue-engineered bile duct becomes popular at present. With the rapid development of materials science and cell biology, the basic research and clinical application of tissue-engineered duct will be more in-depth research and extension, which might bring new ideas and therapeutic measures for patients with biliary defect or stenosis.
ObjectiveTo observe the feasibility of acellular cartilage extracellular matrix (ACECM) oriented scaffold combined with chondrocytes to construct tissue engineered cartilage.MethodsChondrocytes from the healthy articular cartilage tissue of pig were isolated, cultured, and passaged. The 3rd passage chondrocytes were labeled by PKH26. After MTT demonstrated that PKH26 had no influence on the biological activity of chondrocytes, labeled and unlabeled chondrocytes were seeded on ACECM oriented scaffold and cultivated. The adhesion, growth, and distribution were evaluated by gross observation, inverted microscope, and fluorescence microscope. Scanning electron microscope was used to observe the cellular morphology after cultivation for 3 days. Type Ⅱ collagen immunofluorescent staining was used to check the secretion of extracellular matrix. In addition, the complex of labeled chondrocytes and ACECM oriented scaffold (cell-scaffold complex) was transplanted into the subcutaneous tissue of nude mouse. After transplantation, general physical conditions of nude mouse were observed, and the growth of cell-scaffold complex was observed by molecular fluorescent living imaging system. After 4 weeks, the neotissue was harvested to analyze the properties of articular cartilage tissue by gross morphology and histological staining (Safranin O staining, toluidine blue staining, and typeⅡcollagen immunohistochemical staining).ResultsAfter chondrocytes that were mainly polygon and cobblestone like shape were seeded and cultured on ACECM oriented scaffold for 7 days, the neotissue was translucency and tenacious and cells grew along the oriented scaffold well by inverted microscope and fluorescence microscope. In the subcutaneous microenvironment, the cell-scaffold complex was cartilage-like tissue and abundant cartilage extracellular matrix (typeⅡcollagen) was observed by histological staining and typeⅡcollagen immunohistochemical staining.ConclusionACECM oriented scaffold is benefit to the cell adhesion, proliferation, and oriented growth and successfully constructes the tissue engineered cartilage in nude mouse model, which demonstrates that the ACECM oriented scaffold is promise to be applied in cartilage tissue engineering.
The present study is aimed to investigate the early clinical effects of nano-hydroxyapatite/polyamide 66 intervertebral fusion cage (n-HA/PA66 cage) for the treatment of lumbar degenerative diseases. We selected 27 patients with lumbar degenerative diseases who were managed by posterior decompression or reset operation combined with n-HA/PA66 cage intervertebral fusion and internal fixation from August 2010 to January 2012. The oswestry disability index (ODI), low back and leg pain visual analogue score (VAS), and intervertebral height (IH) were evaluated at preoperation, 1 week postoperation and the last follow-up period, respectively. Intervertebral bony fusion was evaluated at the last follow-up time. The patients were followed up for 12-24 months (averaged 19 months). The ODI, VAS and IH were significantly improved at 1 week postoperation and the last follow-up time compared with those at preoperative period (P<0.05). But there was no significant difference between 1 week postoperative and the last follow-up time (P<0.05). Brantigan's standard was used to evaluate fusion at the last follow-up time. There were 19 patients with grade 5 fusion, 8 with grade 4 fusion, with a fusion rate of 100%, and none with grade 1-3 fusions. There was no cage translocation and internal fixation breakage. These results suggested that n-HA/PA66 cage was an ideal biological material in the posterior lumbar interbody fusion and internal fixation operation for treatment of lumbar degenerative diseases. It can effectively maintain the intervertebral height and keep a high rate of bony fusion. The early clinical effect has been satisfactory.
Objective To introduce the development of the collagen materials in drug release and tissue engineering. Methods Literature review and complex analysis were adopted. Results In recent years, some good progress hasbeen made in the studies of collagen, and study on collagen-based materials has become an investigative hotspot especially in tissue engineering. Some new collagen-based drug delivery andengineered materials have come into clinically-demonstrated moment, which willpromote their clinical applications in tissue repairs.ConclusionCollagen has been considered a good potential material in drug release, especially in the tissue-engineering field. To give collagen new characters we should pay more attention to grafting with different function branches through chemistry technique in the future work, except- moderate cross-linking treatment or commingling withother nature or synthesized macromolecules.
【Abstract】 Objective To compare the effect of PLGA and collagen sponge combined with rhBMP-2 on repairing ofarticular cartilage defect in rabbits respectively. Methods PLGA and collagen sponge were made into cyl inders which were 4 mm in diameter and 3 mm in thickness, and compounded with rhBMP-2 (0.5 mg). Defect 4 mm in diameter were made in both of femoral condyles of 24 two-month-old New Zealand white rabbits. The defects in right 18 knees were treated with PLGA/rhBMP-2 composites (experimental group 1), and the left 18 knees were treated with collagen sponge/rhBMP-2 composites (experimental group 2), the other 12 knees were left untreated as control group. At 4, 12 and 24 weeks after operation, the animals were sacrificed and the newly formed tissues were observed macroscopically and microscopically, graded histologically and analyzed statistically. Results From the results of macroscopical and microscopical observation, in the experimental group 1, the defects were filled with smooth and translucent cartilage; while in the experimental group 2, the white translucent tissues did notfill the defects completely; and in the two experimental groups, the new cartilage tissues demarcated from the surrounding cartilage,chondrocytes distributed uniformly but without direction; a l ittle fibrous tissue formed in the control group 4 weeks postoperatively. In the experimental group 1, the defects were filled completely with white, smooth and translucent cartilage tissue without clear l imit with normal cartilage; while in the experimental group 2, white translucent tissues formed, the boundary still could be recognized; in the two experimental groups, the thickness was similar to that of the normal cartilage; the cells paralleled to articular surface in the surface layer, but in the deep layer, the cells distributed confusedly, the staining of matrix was positive but a l ittle weak; subchondral bone and tide mark recovered and the new tissue finely incorporated with normal cartilage;however, in the control group, there was a l ittle of discontinuous fibrous tissue, chondrocytes maldistributed in the border andthe bottom of the defects 12 weeks postoperatively. In the experimental group 1, white translucent cartilage tissues formed, the boundary disappeared; in the experimental group 2, the color and the qual ity of new cartilage were similar to those of 12 weeks; in the two experimental groups, the thickness of the new cartilage, which appeared smooth, was similar to that of the normal cartilage, the chondrocytes arranged uniformly but confusedly; the staining of matrix was positive and subchondral bone and tide mark recovered, the new tissue finely incorporated with normal cartilage; in the control group, a layer of discontinuous fibrous tissue formed in the bottom of the defects 24 weeks postoperatively. Results of histological grade showed that there were significantdifference between experimental group (1 and 2) and control group at any time point (P lt; 0.01); the scores of 12 weeks and 24 weeks in experimental group 1 and 2 had a significant difference compared with that of 4 weeks (P lt; 0.01), there was no significant difference between 12 weeks and 24 weeks (P gt; 0.05), and there were no significant difference between the two experimental groups at the same time point (P gt; 0.05). Conclusion Both PLGA and collagen sponge as a carrier compounded with rhBMP-2 can repair articular cartilage defects.
Objective To investigate the influence of the exogenouscollagen on the function of cells in construction of artificial biotendon.Methods Three materials including human hair, carbon fiber(CF) and polyglycolic acid (PGA) were combined with exogenous collagen and co-cultured with standard transferred human embryonic tenocytes at a concentration of 3×106/mm3 in vitro. The cell number and morphology were observed under inverted microscope and scanning electron microscope after 2 hours, 3 days and 5 days.Results In the artificial biotendon combined with collagen, the cells concentrated around the materials and the cells adhering to the materials turned into round after 2 hours. After 3 days, the adhering cells increased. After 5 days, the shape of the cells changed from round to spindle.ConclusionExogenous collagen will facilitate the cells to adhere onto materials and proliferate.
ObjectiveTo summarize the current research status of alginate derivatives based on biomedical materials, and analyze several key points as novel clinical products.
MethodsThe general preparation and application methods of alginate derivatives based on biomedical materials at home and abroad were reviewed. The present status and problems were analyzed.
ResultsThe derivation methods to prepare alginate derivatives include crosslink, sulfation, biological factors derivatization, hydrophobic modification, and graft copolymerization. With excellent bionic performance of structure and properties, many alginate derivatives are available for tissue engineering scaffolds, artificial organs, and drug delivery systems etc. However, more systematic applied basic research data should be collected and statistically analyzed for risk managements.
ConclusionAlginate derivatives have good feasibility as novel medical products, meanwhile, systematic evaluation and verification should be executed for their safety, effectiveness, and suitability.
OBJECTIVE: From the point of view of material science, the methods of tissue repair and defect reconstruct were discussed, including mesenchymal stem cells (MSCs), growth factors, gene therapy and tissue engineered tissue. METHODS: The advances in tissue engineering technologies were introduced based on the recent literature. RESULTS: Tissue engineering should solve the design and preparation of molecular scaffold, tissue vascularization and dynamic culture of cell on the scaffolds in vitro. CONCLUSION: Biomaterials play an important role in the tissue engineering. They can be used as the matrices of MSCs, the delivery carrier of growth factor, the culture scaffold of cell in bioreactors and delivery carrier of gene encoding growth factors.
OBJECTIVE: To review the research progress and medical application of nano-materials. METHODS: The literature review and comprehensive analysis, methods were used in this study. RESULTS: The Nanotechnology is a typical crossing knowledge. It could be extensively applied in the fields of novel biomaterials, effective transmission of bioactive factor; the detection of functions for all vital organ systems, vascular circulation condition, the control of repair of burn trauma wounds will be monitored by the varied methods of nano technology combined with molecular biological engineering. CONCLUSION: The application of Nanotechnology will play important roles in clinical medicine, wound repair and basic research for the traditional Chinese medicine.
