Biomedical subjects

Tingwu Qin

Publications and source records attributed to Tingwu Qin.

At least 19 recordsLinked to original sources

PubMed2006

[Experimental study on cryopreservation of seeding cells of tissue engineered tendons].

This study sought to find out a good way for the cryopreservation of tendon seeding cells so as to facilitate the preparation of tissue engineering tendons as products. The related questions are how different factors affect cell survival rate at the procedure of preservation and whether cryopreservation affects seeding cells' biological characters as well as collagen secretive function. The results of experiment indicate that DMSO is a more effective cryoprotectant in cryopreservation of tissue engineered tendon seeding cells. Blood serum nourishment is very important in cell culture, preservation and treatment. The same sustenance after cryopreservation increases cell survival rate. In the process of cryopreservation, the concentration of cells is important to cell survival rate; cell survival rate will decrease when it is less than 1.0 x 10(6)/ml. In the process of cryopreservation, the cooling speed is also important to cell survival rate, slow cooling method achieves higher cell survival rate than does the rapid cooling method. Cryopreservation by use of 10%DMSO+15%FCS+75%DMEM does not affect seeding cells' collagen secretive function greatly and does not affect seeding cells' growth curve, cell cycle and chromosome mode obviously. The prescription of 10%DMSO +15%FCS+75%DMEM is suited for the cryopreservation of tendon seeding cells.

Cell Count↗

PubMed2006

[Determination of collagen in tendon by reversed-phase high performance liquid chromatography].

A method for determining collagen in tendon by reversed-phase high performance liquid chromatography (RP-HPLC) was developed. After hydrolysis with hydrochloric acid, the collagen in samples was decomposed into hydroxyproline which hydroxyproline can be derivatized with 2, 4-dinitrochlorobenzene for the determination by HPLC (reversed-phase C18 column, 0.01 mol/L NaAc-HAc (pH 6.0)-CH3CN (80: 20, v/v) as mobile phase, detection at 360 nm). The factors influencing hydrolysis, derivatization and HPLC analysis were studied and optimized. Sixty samples were analyzed with the proposed method. The linear range was from 3 microg/L to 100 mg/L and the detection limit was 3 microg/L. The relative standard deviation (RSD) of determination was 1.95%. The recoveries of spiked samples were 98.4%-110.8%. The results show that the method is sensitive, accurate and suitable for tendon determination.

Chromatography, High Pressure Liquid↗

PubMed2005

[Experimental study on repair of goat tibia defect with marrow stromal cell and bio-derived bone].

OBJECTIVE: To investigate the feasibility of repairing goat tibia defect with marrow stromal cells (MSCs). METHODS: MSCs were cocultured with the bio-derived bone in vitro, and the 20 mm tibia defects were made and fixed with plate in 35 goats, and they were divided into the experimental group, control group and blank group. The defects on the right side were filled with tissue engineering bone as the experimental group, the defects on the left side with bio-derived bone as the control group in 33 goats, and the defect on the both sides were not filled with any materials as the blank group in 2 goats. The repair capability was assessed physically, histopathologically and biomechanically at 2, 4, 6, 8, 12, 16 and 24 weeks after operation in 3 groups. RESULTS: By physical, histopathological and biomechanical examinations, the bio-derived bone was partially absorbed in the experimental group and was rarely absorbed in the control group in the 4th week; the defects were partially repaired in the experimental group, and in the control group, few new bones were observed in the two ends of the implants, in which there was fibrous tissue. The effects of biomechanics had no statistically significant difference between the experimental group and the control group (P>0.05) in the 8th week; the defects were perfectly repaired in the experimental group and the effects of biomechanics had statistically significant difference between two groups (P<0.05) in the 12th weeks. The defects were not repaired in the 24th week in the blank group. CONCLUSION: The tissue engineering bone can efficiently repair bone defect, and its repair capability is better than that of bio-derived bone alone both in quantity and in quality of bone formation.

Animals↗

PubMed2005

[Experimental study on repairing segmental bone defect with bio-derived bone preserved by various methods].

OBJECTIVE: To study the difference of repairing segmental bone defect with bio-derived bone preserved by various methods. METHODS: Freeze-dried biomaterials had been stored in two different preservation solutions for three months, while the biomaterials stored for same period were observed as control group. The experimental model of 15 mm radial segmental defect was made in 60 New Zealand white rabbits, which were divided into groups A, B and C according to transplant materials preserved by various methods. Groups A and B were deeply divided into A1 and A2 subgroups, B1 and B2 subgroups according to whether materials were cocultured with osteoblasts. Tissue engineered bone was used to repair bone defects of left limbs in A1 and B1 subgroups, while simple material to repair defects of right limbs in A2 and B2 subgroups. Group C was divided into C1 and C2 subgroups. Freeze-dried material was used to repair bone defects of the left limbs, while defects of the right limbs as blank control group. The samples were harvested and observed by the roentgenographical, histomorphological, biomechanical and computerized graphical analysis at 4, 8 and 16 weeks. RESULTS: All of the defects treated with implants exhibited new bone formation 4, 8 and 16 weeks postoperatively, increasing with time. The radiological, histomorphological and biomechanical evaluation showed that the ability of new bone formation was arranged in 6 subgroups as follows: A1>A2>C1>B1>B2>C2, the difference was significant between them (P<0.001, P<0.05). The ability of new bone formation was strongest and at 16 weeks the defect was bridged with the appearance of marrow cavities in A1 subgroup, the biomechanical properties in implants approached to those of normal bone. CONCLUSION: The choice of proper preservation solution can improve the ability of repairing bone defect.

Animals↗

PubMed2005

[Expression of interleukin 2 and IL-2 receptor after implanted tissue engineered bones constructed with allogeneic marrow stromal stem cells and bio-derived materials in rhesus monkeys].

OBJECTIVE: To explore the feasibility of allogeneic marrow stromal stem cells (MSCs) as seed cells to construct tissue engineered bone by detecting the expressions of interleukin 2 (IL-2) and IL-2 receptor in rhesus monkeys after implanting these tissue engineered bones. METHODS: Engineered bones were constructed with osteoblasts which derived from allogeneic MSCs and bio-derived materials in vitro, and then were implanted to bridge 2.5 cm segmental bone defects of left radius in 15 rhesus monkeys as experimental group, bio-derived materials only were implanted to bridge same size defects of right radius as control group. Every 3 monkeys were sacrificed in the 1st, the 2nd, the 3rd, the 6th and the 12th weeks postoperatively and the expressions of IL-2 and IL-2 receptor in blood and graft samples were detected quantitatively by enzyme-linked immunosorbent assay (ELISA). RESULTS: There was no significant difference in the contents of IL-2 and its receptor between 2 groups (P>0.05). The contents of IL-2 and its receptor increased from the 2nd week and maintained high level from the 2nd to the 6th week, but decreased after 6 weeks. CONCLUSION: Tissue engineered bones constructed with allogeneic MSCs and bio-derived materials show low immunogenicity. Allogeneic MSCs may be used as seed cells to construct tissue engineered bone.

Animals↗

PubMed2005

[Morphological and biomechanical study on in vivo osteogenesis after repair of cranial defects with plastic engineered bone in rabbits].

OBJECTIVE: To investigate the morphology and biomechanics of in vivo osteogenesis after repairing rabbit skull defects with plastic engineered bone which was prefabricated with alginate gel, osteoblasts and bone granules. METHODS: Twenty-eight rabbits were divided into group A (n=16), group B (n=8) and group C (n=4). The bilateral skull defects of 1 cm in diameter were made. Left skull defects filled with alginate gel-osteoblasts-bone granules (group A1) and right skull defects filled with alginate gel-bone granules (group A2). The defects of group B was left, as blank control and group C had no defect as normal control. The morphological change and bone formation were observed by methods of gross, histology and biomechanics. RESULTS: In group A1, the skull defects were almost entirely repaired by hard tissue 12 weeks after operation. The alginate gel-osteoblasts-bone granule material had changed into bone tissue with few bone granules and some residuary alginate gel. The percentage of bone formation area was 40.92% +/- 19.36%. The maximum compression loading on repairing tissue of defects was 37.33 +/- 2.95 N/mm; the maximum strain was 1.05 +/- 0.20 mm; and loading/strain ratio was 35.82 +/- 6.48 N/mm. In group A2, the alginate and bone granules material partially changed into bone tissue 12 weeks after operation. The percentage of bone formation area was 18.51% +/- 6.01%. The maximum compression loading was 30.59 +/- 4.65 N; the maximum strain was 1.35 +/- 0.44 mm; and the loading/strain ratio was 24.95 +/- 12.40 N/mm. In group B, the skull defects were mainly repaired by membrane-like soft tissue with only few bone in marginal area; the percentage of bone formation area was 12.72% +/- 9.46%. The maximum compression loading was 29.5 +/- 2.05 N; the maximum strain was 1.57 +/- 0.31 mm; and the loading/strain ratio was 19.90 +/- 5.47 N/mm. In group C, the maximum compression loading was 41.55 +/- 2.52 N; the maximum strain was 0.95 +/- 0.17 mm; and the loading/strain ratio was 47.57 +/- 11.22 N/mm. CONCLUSION: The plastic engineered bone prefabricated with alginate gel-osteoblasts-bone granule may shape according to the bone defects and has good ability to form bone tissue, whose maximum compression loading can reach 89% of normal skull and the hardness at 12 weeks after operation is similar to that of normal skull.

Alginates↗

PubMed2005

[Progress in vitreous cryopreservation of living bioproducts].

In this brief review, some key issues related to vitreous cryopreservation of living tissues (natural or engineered), including cells, embryos, tissues, organs, and engineered tissues, are outlined. The principle of vitreous cryopreservation for the biological activity and functionality is demonstrated. The procedures of cooling/ rewarming, composition and function of optimal cryoprotectants, and their effects on bioproducts are described. Vitrification could, therefore, prove to be a useful and effective method of bioproduct cryopreservation for a long period of time, particularly for organized tissues and organs. However, the toxicity of the cryoprotective agents and the devitrification occurring during the rewarming process need additional investigations. Several key areas of research on vitrification are also addressed.

Cryopreservation↗

PubMed2004

[Bio-tribological properties of dental prosthesis made of nitriding titanium alloy material].

Titanium alloy material (TC4) samples were treated with nitriding technique. The dynamic friction and wear behavior of the modified layer were examined on a reciprocating sliding rig in artificial saliva. Microhardness, depth profile and wear mechanisms were investigated by means of MVK-H12, TALYSURF6, XPS and microscopy. The results demonstrate that after being treated with nitriding technique the titanium alloy material (TC4) has better tribological behavior and up-graded wear resistance. The wear mechanism involves adhesion.

Adsorption↗

PubMed2004

[Basic researches on cell adhesion and its application in tendon tissue engineering].

Cell adhesion is a basic and very important tissue in the field of tissue engineering. Fibronectin and integrins are the most important elements to cell adhesion. Some surface receptors of fibroblast can also conjugate with type I collagen in extracellular matrix (ECM) directly. Laminin receptors on the surface of fibroblast bound to laminin also play a role in cell adhesion. In this paper are reviewed a number of related articles. The structures and function of fibronectin and integrins are discussed in detail; the tendon cell's adhesion structures are also discussed. Yet, there was scarcely any paper on the effects which the preservation of tissue engineered products may have on cells' adhesion fo ECM. Therefore, researching on cell adhesion and finding a way of preservation that has no or very little adverse effect on cell adhesion is an important topic. Results from expected advanced researches on cell adhesion may probably find promising applications in the field of tissue engineering.

Cell Adhesion↗

PubMed2004

[Histologic pattern and mechanical properties of tissue-engineered tendon implants for tendon defects].

This is a study on the histologic pattern and mechanical properties of tissue-engineered tendon implanted for treatment of tendon defects. Tendons were resected from Roman chickens. Tendon cells were isolated from the tendons and cultured in vitro. The 2nd-4th passages of tendon cells were seeded on the degradable polyglycolic acid mesh to form cell-scaffold composites, which were further cultured for 7-10 days to construct tissue-engineered tendons. The tendon defects, 0.5 cm-0.8 cm in length, were made in the second digit flexor tendon bilaterally in 20 Roman chickens and then bridged with the constructed tissue-engineered tendons. At 2 weeks, 4 weeks, 6 weeks, and 8 weeks post-operation, the samples of regenerated tendons were collected for gross examination, histologic staining and biomechanical test. After implantation of the tissue-engineered tendons, the wounds healed well. The gross appearance, the cells and collagen fibers arrangement of the regenerated tendons were similar to those of natural tendons, but there were relatively not many closely packed collagen fiber bundles organized in parallel with the tendons ("remodel"), so the maximum tensile force increased slowly and its value was 15.40+/-10.63 N at 8 weeks after surgery, reaching only 23% of that of natural tendon. The maximum strain was 22.49%+/-10.21% at 8 weeks, being 10% higher than that of natural tendons. Polyglycolic acid scaffolds are degraded in vivo so rapidly that the regenerated tendons lose the normal biomechanical stimulus and then are unable to be remodeled. As a result, the mechanical strength of regenerated tendons is much lower than that of natural tendons. These results suggest that the normal biomechanical stimulus may be an important factor for the regenerated tendons to remodel.

Animals↗

PubMed2004

[Possibility of using cartilage cultured in centrifuge tube as a substitute for meniscus].

OBJECTIVE: To compare biological characteristics between articular chondrocyte and meniscal fibrochondrocyte cultured in vitro and to investigate the possibility of using cultured cartilage as a substitute for meniscus. METHODS: Chondrocytes isolated from articular cartilage and meniscus of rabbits aged 3 weeks were respectively passaged in monolayer and cultured in centrifuge tube. Cartilages cultured in centrifuge tube and meniscus of rabbit aged 6 weeks were detected by histological examination and transmission electron microscopy. Growth curves of articular chondrocytes and meniscal fibrochondrocytes were compared; meanwhile, cell cycles of articular chondrocytes and meniscal fibrochondrocytes in passage 2 and 4 were separately measured by flow cytometry. RESULTS: Articular chondrocytes in passage 4 were dedifferentiated. Articular chondrocytes formed cartilage 2 weeks after cultivation in centrifuge tube, but meniscal fibrochondrocytes could not generate cartilage. The differences in ultrastructure and histology obviously existed between cultured cartilage and meniscus; moreover, apoptosis of chondrocytes appeared in cultured cartilage. Proportion of subdiploid cells in articular chondrocytes passage 2 and 4 was markedly higher than that in passage 2 and 4 fibrochondrocytes (P < 0.05). CONCLUSION: Meniscal fibrochondrocytes can not form cartilage after cultivation in centrifuge tube, while cartilage cultured in centrifuge tube from articular chondrocytes can not be used as graft material for meniscus. Articular cartilage is markedly different from meniscus.

Animals↗

PubMed2004

[The cryopreservation technology in research and development of tissue engineered products].

In this brief review, some key issues related to cryopreservation of seeding cells, scaffolds, and engineered tissues are outlined. The importance of cryopreservation technology to the research and development of tissue engineered products is demonstrated. The biological or biochemical reaction rate must be reduced or completely shut off in order to preserve the tissue engineered products for a long period of time. Cryopreservation may be one of the possible approaches to the fulfillment of this requirement. Seeding cells are stored at low temperature. Tissue engineered scaffold products are usually lyophilized. Engineered tissues are preserved by vitreous cryopreservation technology.

Cell Count↗

PubMed2004

[Recent researches on the responses of fibroblasts exposed to cyclic mechanical stretching in vitro].

Recently, in vitro dynamical cell-culture has been drawing more and more attention from researchers in the areas of tissue engineer, and a series of researches have demonstrated that cyclic mechanical stretching has significant effects on the cell proliferation, differentiation, and on the cell alignment on scaffold, as well as on the synthesis of extracellular matrix, cytokines, and matrix metalloproteinases (MMPs). By focusing on reviewing the culture of several kinds of fibroblasts in vitro, we learned that these cellular responses mentioned above induced by cyclic mechanical stretching were tested by many precisely designed experiments, and assumed that cyclic mechanical stretching, if applied properly, would contribute significantly to our purpose of constructing more sophisticated tissue-engineered tendon and ligament.

Cell Differentiation↗

PubMed2003

[The related research of tissue-engineered tendon in vivo].

Using tissue-engineered tendons to repair tendons and ligaments as well as functional reconstruction is the focus of nowadays researches. The scaffolds must be not only unharmful to health, but also easy for cells attachment, and be able to induce collagen deposition to form a neotendon with mechanic properties similar to those of normal tendon. In recent researches, it has been found that the mechanic properties of the implants change with the degrading and femdonizing of scaffolds. The relationships between collagen deposition, scaffolds degradation and mechanic properties of neotendon need to be defined more clearly.

Animals↗

PubMed2003

[Biomechanical properties of tissue-engineered tendons after repairing digital flexor tendons in chickens].

Experiments have been performed to investigate why the biomechanical strength of repaired tendons is lower than that of the normal tendon when the engineered tendons are implanted in vivo to replace the tendon defects. We seeded the primary culture tendon cells derived from Roman chickens' digital flexor tendons on the degradable polyglycolic acid meshes to construct tissue-engineered tendons. The flexor tendon defects (0.5 cm-0.8 cm) excised in second digit bilaterally in 20 Roman chickens, had been repaired with the constructed tissue-engineered tendons. The samples of repaired tendons were collected at 2, 4, 6 and 8 weeks after operation. Tests for scaffold weight, hydroxyproline content, and mechanical strength of the samples were performed. We found that from 2 weeks to 8 weeks afteroperation, the weight of the scaffolds decreased significantly, almost disappearing at 8 weeks; the hydroxyproline content determining the total collagen content increased gradually without significance; mechanically, both energy at break and tensile strength showed a tendency of drastic decrease at first 4 weeks afteroperation and a gradual increase afterwards, but the tensile strength at 8 weeks afteroperation was only 23% of that of the normal tendon. We conclude that the lower biomechanical strength of repaired tendons is owing to the serious mismatch between scaffold degradation and collagen synthesis.

Achilles Tendon↗

PubMed2002

[Experimental studies on procedures and properties of natural derived scaffold materials of tissue engineered bone].

To detect the properties of natural xenogeneic bone derived materials which were processed with different physical and chemical treatments, we made fully deproteinized bone(FDB), partially deproteinized bone (PDPB), partially decalcified bone(PDCB) from pig ribs. Their morphological features, constitute components and mechanical properties were examined by scanning electron microscopy, x-rays diffraction analysis, mechanical assay and so on. The results showed that FDB, PDPB and PDCB maintained natural network pore system. The ratios of calcium to phosphorus were 1.81, 1.74 and 1.50, and the protein contents were 0.01% +/- 0.02%, 22.41% +/- 0.83% and 35.75% +/- 2.12% respectively. The sequence of their mechanic strength was PDCB > PDPB > FDB. These data indicate that FDB, PDPB and PDCB possess natural network pore system. Their organic and inorganic component ratios and contents are different, so their mechanic properties are not alike. Additionally, more investigations will be necessary to detect the biocompatibility of the three different scaffold materials of natural derived bone.

Animals↗

PubMed2002

[A tissue-engineered strain scaffold for three-dimensional cell cultures].

This article introduces a three-dimensional scaffold which is used to perform three-dimensional cell culture under mechanical stretch from the point of construction of tissue-engineered tissue. The composition, structure, surface characteristics, mechanical property, and cell compatibility of the scaffold have been studied by using surface chemistry and material mechanics testing methods. The results indicate that the polyvinyl alcohol (PVA) sponge, which is water-tolerant, coated with Poly-DL-lactic-co-glycolic acid (PLGA) possesses a good nature in appropriate surface feature, porosity, elastic recoil, and cell compatibility. These features provide wide options for using this scaffold to study the effects of mechanical stretch on cells maintained in three-dimensional culture to provide a three-dimensional matrix.

Biocompatible Materials↗

PubMed2002

[Experimental studies on histocompatibility of three bio-derived bones].

OBJECTIVE: To study the histocompatibility of three bio-derived bones. METHODS: After treatment with different physical and chemical method, three bio-derived bones, the composite fully deproteinized bone (CFDB), partially deproteinized bone (PDPB) and partially decalcified bone (PDCB) were implanted into rabbits. The toxicity, immune response and subperiosteum osteogenesis of CFDB, PDPB and PDCB were studied through gross observation, serum antibody measurement, evaluation of local cellular immune response and HE staining. RESULTS: The study showed that CFDB, PDPB and PDCB had no toxicity. They could conduct peripheral tissue to grow into them and had no harmful effect on subperiosteum osteogenesis. They could also promote cartilage and osteoid tissue derived from periosteum to calcify to new bone, and combine with the peripheral bone. The degree of immune response caused by them was in the sequence of PDCB > PDPB > CFDB. CONCLUSIONS: The three bio-derived bones, CFDB, PDPB and PDCB have good histocompatibility.

Animals↗