Biomedical subjects

Shi-bi Lu

Publications and source records attributed to Shi-bi Lu.

11 recordsLinked to original sources

PubMed2006

[Biological characterization of rabbit's articular chondrocytes by confluent culture in vitro].

OBJECTIVE: To obtain large amount of differentiated chondrocytes in vitro, examine and compare the biological characterization of rabbits' articular chondrocyte cultured in different density in vitvo. METHODS: From November 2001 to June 2004, articulate tissues were obtained from the joints of the adult rabbits. Chondrocytes were isolated from the cartilage tissue with type II collagenase digestion and cultured in DMEM/F-12 supplemented with 20% fetal bovine serum (FBS). The chondrocytes were cultured with low density of monolayer culture and high density of confluent culture respectively. The differentiated phenotype was evaluated by histochemistry or immunohistochemistry. RESULTS: When chondrocytes cultured in monolayer and in low density, it proliferated rapidly during the three generations, but with the same time, dedifferentiation was also rapid. After the third passage, most of the passage cells lost the phenotype, and the proliferation also stagnated. While chondrocytes cultured in high density, dedifferentiation slowed down. And even the phenotypes of the dedifferentiated chondrocyte which were cultured in low density could reduced partly by followed high density culture. CONCLUSIONS: Culture chondrocytes by high density in vitro can effectively maintain the differentiated phenotype of chondrocyte. It also keeps the proliferation character as monolayer culture. The dedifferentiated chondrocyte caused by many passages could redifferentiate partly. So it is indicated that confluent culture of original or expanded chondrocytes in high density is a better culture methods than culture in low density.

Animals↗

PubMed2006

[Joint resurfacing using allograft chondrocytes embedded in alginate gel].

OBJECTIVE: To explore the feasibility of repairing the articular cartilage with allo-articular chondrocytes embedded in alginate gel. METHODS: Allo-articular chondrocytes were isolated from three adult New zealand rabbits. The cells were cultured in DMEM/F-12 supplemented with 20% fetal bovine serum (FBS). Chondrocytes of 2nd - 3rd passage were harvested and were diluted to 5.0 x 10(7) cells/ml with 1.2% alginate. Then alginate gel was formed by 102 mM CaCl(2). The gels were cultured subsequently for 1 week and then transferred to the full-thickness defects in the femoral condyles of adult rabbits. In control group the defects were left untreated. The animals were sacrificed in the 3rd and 6th month after operation respectively. The specimens were decalcified with 50% formic acid. The histologic sections were stained with safranin O-fast green, hematoxylin-eosin (H&E) and picric acid-Sirius red and immunohisto-stained for type II collagen and aggrecan. The repairing efficiency was evaluated according to Wakitani scoring. RESULT: In the experiment group all 8 defects acquired repair, 7/8 were repaired with mature hyaline cartilage tissue, and 1/8 was with fibrocartilage tissue for less cell-gel inputted. The thick of repaired tissues were closed to the normal and the tissue integrated smoothly with cartilage around the defects. Safranin O staining of the matrix acted in accordance with the normal and immunostaining for type II collagen and aggrecan showed positive. Picric acid-Sirius red staining showed that the chondrocytes lined in lines and the collagen aligned like Gothic architecture structure by polarization microscopy. There was no evidence of residue of alginate and inflammation in 3rd month specimens and no obvious deterioration at 6th month. But in control group, only a small amount of fibrous, fibrocartilage, or hyaline-like tissue was seen on the surface of the defects. Wakitani scoring showed 1.75 points for the experiment group and 7.65 for the control group. CONCLUSION: It is a promising way to repair the articular cartilage with homogeneous articular chondrocytes embedded in alginate gel.

Alginates↗

PubMed2006

[Influences of decellularization processes on immunogenicity of chemically acellular nerve allografts].

OBJECTIVE: To investigate the relationship between immunogenicity and decellularization processes of chemically acellular nerve allografts. METHODS: Adult Sprague Dawley rats were used as nerve donors and adult male Wistar rats used as nerve recipient hosts. 25 mm nerve segments were excised from SD rats' sciatic nerves. The nerve segments were decellularized via an improved chemical decelluarization treatment as follows: (1) nerve segments were rinsed with cold sterile Ringer's solution; (2) stabilized by pinning the ends to a thin plastic support, and submerged in 4% Triton-100 solution 12 h; (3) soaked into 3% sodium deoxycholate for 12 h; (4) washed in distilled water for 6 h. The procedures were repeated once again. The acellular nerve allografts from SD rats were sterilized by gamma irradiation and implanted into Wistar rats subcutanously. The control group was implantation of fresh nerve allografts from SD rats. The immunogenicity of acellular nerve allograft was tested by immunohistochemical examination of the intensity of CD3(+), CD4(+) and CD8(+) cells that infiltrated the allografts. Ulnar nerve segments were obtained from forearms of dogs and decellularized according to above procedures. According as the decellularization times, The ulnar nerve segments were divided into three subgroups: in group I, group II and group III, the nerve segments were decellularized repeatedly two, three and four cycles respectively. Each ulnar nerve segment was subdivided into five portions from proximal to distal end. The degrees of decellularization, demyelination and basal lamina integrity of extracellular matrix scaffold were observed with microscope and assessed by a score system. The immunohistochemical staining of GAG was observed. RESULTS: The intensity of CD3(+), CD4(+) and CD8(+) T cells that infiltrated the allografts was greatly lower in acellular nerves than in fresh nerves. The mild cell-mediated host-graft immunorejection in acellular nerves was observed. On the decellularization procedures, the cells were completely extracted from nerves in all groups, but the myelin sheath were partially existed, and the GAG was present in the basal membrane of myelin sheath. In the score of demyelination, there were no statistical differences between groups (P > 0.05). The statistical difference of basal lamina integrity scores between group I and group II, group I and group III were significant (P < 0.05). As increasing the times of process, the degrees of disintegrity of basal lamina was significantly enhanced. CONCLUSIONS: Although decellularization processes significantly reduce the cell-mediated immunorejection of acellular nerve allografts, it can induce mild immunoreaction all the same, the antigen that responsible for immunogenicity may be the residual component of GAG in myelin sheath.

Animals↗

PubMed2005

[The preparation, structure evaluation and preliminary application of biomimetic biphasic calcium phosphate scaffold].

OBJECTIVE: To fabricate biomimetic biphasic calcium phosphate BCP ceramic scaffolds using three-dimensional (3D) gel-lamination technology and evaluated their structure with 3D parameters and related method. METHODS: Series two-dimensional images of femoral head's specimen of dogs were obtained by micro-computed tomography (Micro-CT). According to these images, porous biomimetic biphasic calcium phosphate (BCP) ceramic scaffolds with oriented trabecular structure were fabricated by three-dimensional (3D) gel-lamination technology. And then, the three-dimensional structure of the scaffolds were reconstructed by computer according to Micro-CT images of these scaffolds and evaluated by three-dimensional parameters. These parameters included bone volume fraction (BVF, BV/TV), bone surface/bone volume (BS/BV) ratio, trabecular thickness (Tb.Th), trabecular number (Tb.N), trabecular spacing (Tb.Sp) and structure model index (SMI). The biomechanical properties and biocompatibility of these scaffolds were also evaluated in the study. Six scaffolds, which were combined with BMCs (bone mesenchymal cells, BMCs), were planted into the bone defect of six dogs' femoral head respectively. RESULTS: There was no significant difference between trabecular samples and BCP scaffolds in BV/TV, Tb.Th, Tb.N, and Tb.Pf (P > 0.05). The trabecular system of the scaffold, which had some orientation, represented plate-like model. With a micro-porous porosity of 62%, the average compressive modulus and ultimate strength along the axis of the scaffolds reached (464.0 +/- 36.0) MPa and (5.6 +/- 0.8) MPa respectively. The results of animal test indicated that the trabeculae of these scaffolds were covered by a layer of new bone after 10 weeks of operation. CONCLUSION: Porous BCP scaffolds have been produced with oriented microarchitectural features designed to facilitate vascular invasion and cellular attachment and with initial mechanical properties comparable to those of trabecular bone.

Animals↗

PubMed2005

[Comment on some spinal surgery].

Bone tumor metastases is relatively common. Approximately 5%-20% of spinal metastatic tumors will finally invade the spinal cord and exacerbate symptoms. The adoption of combined approach in recent years has significantly increased the survival rate. After excision of the tumors, internal fixation instrumentations are needed to stabilize the vertebrae. These procedures must be performed under the condition that the patients can tolerate the operation. Fused vertebra with instrumentation may cause degenerative diseases at the adjacent segments, which has been a problem of concern recently. Results of biomechanical tests indicated that these degenerative changes are related to the increased motion range of the neighboring segments. An old view is "the more rigid the instrumentation is, the better the results are", which has been disproved by clinical evidences. Improper use of internal spine fixation instrument should be avoided. Artificial intervertebral disc replacement can produce favorable short-time effects, however, its long-term effects and complications still requires further observations.

Humans↗

PubMed2004

[Long-term clinical observation on the repair of large articular cartilage defects of the hip and the knee with free autogeneous periosteum].

OBJECTIVE: To observe the long-term clinical results of repairing large articular cartilage defects of the hip and the knee with free autogeneous periosteum. METHODS: Based on the results of experimental studies, the authors used free autogeneous periosteum transplantation and postoperative continuous passive motion (CPM) to repair large articular cartilaginous defects in 52 patients from February 1987 to August 1995. Of 37 patients with complete follow-up data, 16 had congenital dislocation of the hip, 6 traumatic arthritis of hip, 1 femoral head destruction following mild infection, 2 ankylosing spondylitis, 6 intra-articular fracture of the knee, 4 arthritis of the knee and 2 stiff knee following joint infection. The patients with dislocation of hip were given relieving traction before operation. The cartilages of pathological changes were excised to bleeding bone. The defects were repaired with periosteum removing from tibia. CPM were immediately applied for 4-6 weeks and no bearing was allowed 6 months after discharge. The silicon membrane was taken out in the 6th month. RESULTS: Thirty-seven patients (17 males, 20 females) were followed up 7-15 years with an average of 10.5 years. The functional evaluation referred to joint pain degree, joint mobile range, daily activity and X ray findings. The results were excellence in 11 patients, good in 18 patients, poor in 8 patients. CONCLUSION: The method to repair articular cartilage defect with free autogeneous periosteum is effective and may be applied clinically.

Adolescent↗

PubMed2003

[Acellular nerve allograft by chemical extraction in humans].

OBJECTIVE: To develop a procedure by which Schwann cells and myelin in the peripheral nerve could be removed while the basal lamina tubes remained intact, and to obtain a thick and long acellular nerve allograft in humans. METHODS: Four ulnar nerves 10.0 cm long and 4.0 - 5.0 mm in diameter were excised from a donated male body and cleaned from external debris. The nerves were treated with a solution of Triton X-100 and a solution of sodium deoxycholate at room temperature. After a final wash in water, the nerves were stored in phosphate-buffered saline (PBS, pH 7.2) at 4 degrees C. HE, luxol fast blue and fibrin staining were performed to visualize cells, myelin and basal membranes respectively and immunohistochemical staining was performed to visualize the presence of laminin, a Schwann cell lamina component, both in fresh and acellular nerve segments. To reveal overall structure better, methylene blue-fuchsin staining was performed in semithin section. The ultrastructure of acellular and fresh nerves were observed and photographed in a transmission electron microscope. RESULTS: The acellular human ulnar nerve was white long cylinder with well elasticity and ductility. HE, myelin and fibrin staining revealed that cells, axons and myelin sheath were removed and basal membrane was preserved after extraction procedure. Staining for the presence of laminin showed that the Schwann cell basal lamina component were present in the nerves after chemical treatment. Methylene blue-fuchsin staining and transmission electron microscopy showed that the myelin sheaths were absent in the extracted nerve segments and empty basal lamina tubes remained in the endoneurium. CONCLUSIONS: We developed an extracted procedure with the detergents of Triton X-100 and deoxycholate, by which cells, axons and myelin sheaths could be removed from a human ulnar nerve while the basal lamina tubes remain intact and a thick long acellular nerve allograft is obtained. The laminin, a Schwann cell basal lamina component, can be preserved in the acellular nerve.

Adult↗

PubMed2003

[An experimental study of demineralized bone matrix to repair bone defects as a scaffold of tissue engineering].

OBJECTIVE: To evaluate application of the sponge of demineralized bone matrix (SDBM) in tissue engineering of bone. METHODS: SDBM was prepared from long bone of rabbits. Bone marrow cells were flushed from the bone shaft of femurs of a two-month-old New Zealand white rabbit. After the cells were cultured for 9 days, the flasks were added into dexamethasone (10(-8) mol/L), beta-glycerophosphate sodium (10 mmol/L) and L-ascorbic acid (50 micrograms/ml). After 5 weeks, the cultured cells were collected and marked by 5-Bromo-2'-dexyouridine (BrdU). The grand sum of cells seeded on a piece of SDBM was about (4-6) x 10(6). The composites of cells and SDBM (tissue engineered chip, TEC) were implanted into muscles and bone defects of radius in rabbits. A standard procedure was applied to make a 10 mm long defect bilaterally in the radius of nine skeletally mature male New Zealand white rabbits. All of the 18 defects were randomly divided into three groups: group I, six defects were grafted by TEC; group II, six defects were grafted with SDBM alone; group III, six defects were empty. RESULTS: The results of radiographic and histological evaluation showed that all of the defects were repaired in group I and group II at 6 weeks, none of the defects was repaired in group III. The results of BrdU staining showed that the staining was positive in group I, but negative in group II. Biomechanical test showed that the compressive ultimate strength (CUS) of new bone in TEC implanted group was comparable with normal radius (P = 0.623) and in SDBM implanted group was significant lower than normal radius (P = 0.038). CONCLUSIONS: The TEC can form cartilage and bone tissue in muscles and repair segmental bone defects. SDBM is a kind of effective natural scaffold in tissue engineering of bone.

Animals↗

PubMed2002

[Experimental study on repair of articular cartilage defect in large area with chondrocytes cultured on fascia].

OBJECTIVE: To study the biological characteristic and potential of chondrocytes grafting cultured on fascia in repairing large defect of articular cartilage in rabbits. METHODS: Chondrocytes of young rabbits were isolated and sub-cultured on fascia. The large defect of articular cartilage was repaired by grafts of freeze-preserved and fresh chondrocytes cultured on fascia, and free chondrocytes respectively; the biological characteristic and metabolism were evaluated by macroscopic, histological and immunohistochemical observations, autoradiography method and the measurement of nitric oxide content 6, 12, 24 weeks after grafting. RESULTS: The chondrocytes cultured on fascia maintained normal growth feature and metabolism, and there was no damage to chondrocytes after cryopreservation; the repaired cartilage was similar to the normal cartilage in cellular morphology and biological characteristics. CONCLUSION: Chondrocytes could be cultured normally on fascia, which could be used as an ideal carrier of chondrocytes.

Animals↗

PubMed2002

[Shape, phenotype and gap junction of the rabbit chondrocytes].

OBJECTIVE: To study the gap junction and phenotype of cultured chondrocyte of rabbit, and the gap junction between the chondrocytes in the same cartilage cavities in human femoral head articular cartilage. METHODS: CFDA-AM was added into the medium of the fifth passage of chondrocyte of rabbit in the 96-well plate. The fluorescent in spherical and fibroblast-like chondrocytes was detected separately. The recurrence of the fluorescent in accordant with time in 16 minutes was recorded after blanching the fluorescent with laser. And the fluorescent after blanching of chondrocyte in the cartilage cavities in the proliferative zone of articular cartilage of adult human femoral head was recorded, too. RESULTS: The average fluorescent of the single layer of the fibroblast-like chondrocyte was 83(ranged from 1 to 274), the highest was found in the spherical shaped cell (averaged 2,057, ranged from 340 to 3,538). The recurrence of the fluorescent after the blanching appeared only in the spherical chondrocyte, the gap junctions reappeared only in the spherical chondrocytes, as well as in the cells in the cartilage cavities in the articular cartilage of the human femoral head. CONCLUSION: The appearance of the gap junction is corresponded with the spherical shape, secretion of the cartilage matrix of the chondrocyte. There are gap junctions in the cells in the same cartilage cavities in the articular cartilage of the human femoral head, while no gap junctions in the isolated chondrocytes in the cartilage.

Animals↗

PubMed2002

[The position and application of nanotechnology in the development of life science].

In this article, the position of nanotechnology and its effects on life science are concisely discussed, including the effects of nanotechnology on biology, on the study of new type biomaterials, on the development of new drugs, on diagnosis and therapy methods. The importance of nanotechnology in life science is summarized, and the application and development of nanotechnology in life science are also discussed.

Biocompatible Materials↗