Biomedical subjects

Xiuqun Li

Publications and source records attributed to Xiuqun Li.

16 recordsLinked to original sources

PubMed2006

Histologic evaluation of direct pulp capping with a self-etching adhesive and calcium hydroxide in beagles.

OBJECTIVE: To evaluate the pulpal response of beagles following direct pulp capping with Clearfil SE Bond (SB), a self-etching adhesive. STUDY DESIGN: One hundred thirty sound teeth from 6 male beagles were used. One hundred twenty teeth had their pulp mechanically exposed at the bottom of the class V cavities and were divided into 2 groups. In group 1, teeth were capped with SB; group 2 teeth were capped with calcium hydroxide cement (CH). Ten teeth were kept intact as an untreated control group. After 7, 30, and 90 days, 40 teeth from 2 beagles were extracted and processed for light microscopic examination. RESULTS: After the 7-day observation period, inflammatory reaction in the SB group was similar to that of the CH group (P > .05). After the 30-day and 90-day observation periods, inflammatory reaction was slight in both groups, but less dentin bridge formation was observed in specimens from the SB group than in those from the CH group (P < .05). CONCLUSION: SB showed good biocompatibility with pulp, but its ability to induce reparative dentin was lower than that of CH.

Animals↗

PubMed2006

[A comparative study on acellular small intestinal submucosa and acellular amnion as dressings for traumatic skin defects].

OBJECTIVE: To compare the reparative effects between the acellular small intestinal submucosa and the acellular amnion as dressings for traumatic skin defects. METHODS: Three full-thickness skin defects, which were close to the vertebral column of the pig, were created on both sides of the dorsum. The skin defects were randomly divided into three groups. In each group, the following different materials were used to cover the skin defects: the acellular amnion in Group A, the acellular small intestinal submucosa (SIS) in Group B, and the physiological saline gauze in Group C (the control group). The specimens from the skin defects were harvested for a histological evaluation and for determination of the hydroxyproline content at 10 (2 pigs), 20 (2 pigs), and 30 days (3 pigs). We observed the healing process of the wound and its healing rate, counted the inflammatory cells, vascular endothelial cells, and proliferating cells, and determined the hydroxyproline content. RESULTS: The acellular amnion in Group A and the acellular SIS in Group B adhered to the wound tightly, but they did not adhere to the dressing; when the dressing was changed, the wound did not bleed. The saline gauze in Group C adhered to the wound tightly, but when the dressing was changed, the wound bled until 22 days after operation. Under the microscope, the collagen in the tissue below the epithelium was arranged more regularly and there were fewer cells concerned with inflammation in Groups A and B than in Group C at 10, 20, and 30 days after operation. At 10, 20, and 30 days after operation, the wound healing rate was greater in Groups A and B than in Group C. The number of the inflammatory cells and the proliferating cells were greater in Group C than in Groups A and B. There was a statistically significant difference (P < 0.05), At 20 and 30 days after operation, the content of hydroxyproline was greater in Group C than in Group A and B. There was a statistically significant difference (P < 0.05). However, there was no statistically significant difference between Group A and Group B in the wound healing rate, the numbers of the inflammatory cells, vascular endothelial cells and proliferating cells, and the content of hydroxyproline (P > 0.05). There was no statistically significant difference among the three groups in the number of the vascular endothelial cells. CONCLUSION: Compared with Group C, the wound healing rate is improved, the collagen in the tissue below the epithelium is arranged more regularly, and the inflammatory cells, bleeding, and effusion are reduced in Groups A and B. The reparative effects of the acellular amnion and the acellular small intestinal submucosa as dressings on the skin defects are almost the same.

Amnion↗

PubMed2006

[Experimental study on porcine keratinocytes cultured and purified rapidly and cocultured on acellular amnion in vitro].

OBJECTIVE: To explore an effective method to culture and purify porcine keratinocytes, to observe the morphological characteristics of porcine keratinocytes growing on acellular amnion and to offer the experimental basis for that the amnion is used for tissue engineering. METHODS: The primary porcine keratinocytes were cultivated with DKSFM (Defined keratinocyte-SFM) containing 10% fetal bovine serum (FBS). The second passage porcine keratinocytes were cultivated with the medium of DKSFM containing different concentrations of FBS. Because of the speciality that keratinocytes stick to flask fast, we purified the keratinocytes by 0.02% EDTA and 0.05% trypsin step by step. The second passage keratinocytes were seeded on amnion, the keratinocytes/amnion composites were observed by dye directly, histopathology and immunohistochemical staining. RESULTS: The proliferation of the primary porcine keratinocytes cultured with the medium of DKSFM containing 10% FBS was fast and the morphological characteristics were good. The cultivated porcine keratinocytes expanded to 60%-70% of the total area of the bottle of the flask after 5 days. The proliferation of the second passage porcine keratinocytes cultivated with the medium that DKSFM containing 5% FBS was faster than the second porcine keratinocytes cultured with the medium of DKSFM containing 10% FBS, or DKSFM without FBS. The proliferation of the second passage porcine keratinocytes cultivated with DKSFM without FBS was the slowest one among the 3 medium. The porcine keratinocytes that were purified by 0.02% EDTA and 0.05% trypsin step by step were got with high pure. After the keratinocytes were cultivated on the surface of amnion 12 days, the keratinocytes form a single layer on the surface of amnion and the cells were polygon and arranged like slab- stone. After 14 and 16 days, the cells contacted more closely. But at 16 days after the cells were seeded, some of the cells got aging. CONCLUSION: To culture primary porcine keratinocytes with the medium that DKSFM containing 10% FBS and to cultivate the second passage with the medium containing 5% FBS, the proliferation of porcine keratinocytes are faster. The method that purify the porcine keratinocytes is effective. Acellular amnion offers excellent bioscaffold to support keratinocytes to adhere and grow. After the porcine keratinocytes are cultivated on the surface of the acellular amnion 12 days, the morphologic characteristics are better than that of other groups.

Actihaemyl↗

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

[Experimental study on repairing segmental bone defects with three bio-bone derived materials].

OBJECTIVE: To evaluate the osteogenesis of three bio-bone derived materials in repairing segmental bone defects. METHODS: Sixty Japanese rabbits were made 10 mm radius segmental defects and divided into 5 groups (groups A, B, C, D and E, n=12). Composite fully deproteinised bone (CFDB, group A), partially deproteinised bone (PDPB, group B), partially decalcified bone (PDCB, group C), autogenous iliac bone graft (group D) and no implant (group E) were implanted into the radius segmental bone defects of rabbits. The specimens were examined after 4, 8, 12 and 24 weeks; the osteogenesis was evaluated through X-ray radiograph and undecalcified solid tissue histological examination. RESULTS: The border between the material and host's bone was distinct after 4 weeks and blurred after 8 weeks; the density of partial edge of the material was similar to that of radii after 12 weeks. The medullary cavity of bone reopened in group B; the density of most defect area was similar to that of the host bone and there was a few high density shadow in group C; the density of most defect area was higher than that of host bone in group A after 24 weeks. There was no significant difference in radiograph scoring between groups A, B and C after 4 weeks and 8 weeks (P>0.05); the scores of group B and C were higher than that of group A after 12 weeks (P<0.05); and the scores were arranged as follow: group D > group B > group C > group A after 24 weeks (P<0.05). Bone callus grew toward defect area and new bone adhered to the material after 4 weeks and 8 weeks; more new bone formed, and the materials were absorbed and degraded with time. The quantity of bone formation was more in group D than in group B and in group B than in group C and in group C than in group A after 24 weeks (P<0.05). CONCLUSION: PDPB had good osteogenesis in repairing the segmental bone defect, PDCB was inferior to it, both PDPB and PDCB are fit to repair segmental bone defect. Both of them were inferior to autogenous 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

[Experimental studies on preparation and property of scaffold material of bio-derived bone loading wo-1].

OBJECTIVE: To provide the chosen scaffold materials for experiment and application of tissue engineering and to detect the properties of the collagen bio-derived bone scaffold material loading WO-1. METHODS: The pure bio-derived bone scaffold material, bio-derived bone scaffold material loading collagen, collagen bio-derived bone scaffold material loading WO-1 were made by use of allograft bone, and type-I collagen, and WO-1. The morphological features, constitute components and mechanical properties were examined by scanning electron microscopy, X- rays diffraction and mechanical assay. RESULTS: The bio-derived bone scaffold material maintained natural network pore system; the bio-derived bone scaffold material loading collagen maintained natural network pore system, the surface of network pore system was coated by collagen membrane; the collagen bio-derived bone scaffold material loading WO-1 maintained natural network pore system, the surface of network pore system was coated by collagen membrane. The pore sizes of the 3 materials were 90-700 microm, 75-600 microm and 80-600 microm, respectively, and the porosities were 87.96%, 80.47%, 84.2%. There was no significant difference between them (P>0.05). The collagen bio-derived bone scaffold material loading WO-1 consisted of [HA,Ca10 (OH)2 (PO4)6. There was no significant difference in the mechanical strength of the three scaffold materials. CONCLUSION: The bio-derived bone scaffold material loading WO-1 is as good as bio-derived bone scaffold material and collagen bio-derived bone scaffold material, and it is an effective scaffold material for tissue engineering bone.

Biocompatible Materials↗

PubMed2004

[Application of hard tissue slicing in research of bone tissue engineering].

OBJECTIVE: To improve the method of hard tissue slicing for research of bone tissue engineering. METHODS: The method of hard tissue slicing especially the key technique-slice mounting had been studied and improved. RESULTS: The experiments showed that our research improved techniques in hard tissue slicing not only in keeping the characteristics of hard tissue slicing, easily stain with HE, Masson, immunohistochemistry, and distinguishing the differences among tissues easily, but also in overcoming the shortcoming of issue shedding easy to happen in the general hard tissue slicing. CONCLUSION: The improved techniques in hard tissue slicing is a more useful hard tissue slicing techniques.

Animals↗

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

[Effect of human acellular amnion membrane on tendon adhesion in rat].

OBJECTIVE: To investigate the effects of human acellular amnion membrane on SD rat tendon adhesion and to obtain the experimental data for clinical application in preventing postoperative tendon adhesion. METHODS: The tendons of 28 adult SD rats hindlimb were cut and sutured. The tendons of left hindlimb were encapsulated by human accellular amnion membrane as the experimental group and the ones of the other side were not encapsulated as control group. The rats were killed 1, 2, 4, 6, 8 and 12 weeks after operation. The results were evaluated grossly and histologically. RESULTS: There were no differences in healing of injury tendon and inflammatory response between the two groups. The anatomical and histological results showed the experimental group had less adhesion than the control group (P < 0.05). CONCLUSION: Human acellular amnion membrane can prevent adhesion of tendon without affecting tendon healing and is an optimal biological material to prevent tendon adhesion.

Amnion↗

PubMed2004

[Cellular compatibility of small intestinal submucosa in vitro].

This study was aimed to evaluate the cellular compatibility of the small intestinal submucosal(e) (SIS). Prepared by use of pig jejunum. SIS were cocultured with human embryonic periosteal osteoblasts (HEPOB), human embryonic skin fibroblasts (HESFB) and rabbit renal vascular endothelial cells (RRVEC) respectively. The cell growth, attachment, cell cycle, cell apoptosis rate were detected to evaluate the cellular compatibility of SIS. The three kinds of cells attached onto SIS and grew well. SIS accelerated the growth of RRVEC. No effects of SIS were detected on cell cycle and cell apoptosis rate in the three kinds of cells. SIS has good cellular compatibility without cytotoxicity. The porous structure of SIS is suited for the growth of HEPOB, HESFB and RRVEC in three dimensions in the scaffold. SIS is a good bio-derived material of tissue engineering.

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 reconstruction of extensive anterior defect of rabbit trachea with the use of free auricular cartilage].

OBJECTIVES: To determine whether free auricular cartilage grafts can be used to reconstruct the extensive anterior defect of rabbit trachea and observe the difference between autograft and allograft. METHODS: Twenty New Zealand white rabbits were divided into autograft group (n = 10) and allograft group (n = 10). All grafts were taken from the right auricle, and defect included 8 to 10 rings of trachea. The gross morphorlogical features, endoscopic examinations, biomechanic determinations and histological findings of grafts were assessed at 1,2,4,8 and 12 weeks after operation. RESULTS: Eighteen rabbits survived. Mild tracheal stenosis was observed under endoscope. The maximum stress per mm at 0,4,8 and 12 weeks was 2.54 +/- 0.19, 1.31 +/- 0.21, 1.72 +/- 0.22 and 1.96 +/- 0.08 kPa/mm, respectively. Histological analysis revealed that the viable chondrocytes and neochondrocytes at 12 weeks accounted for 62.0% +/- 3.45%, 65.89% +/- 48% in the autograft group and 60.1% +/- 3.98%, 55.20% +/- 7.57% in the allograft group. No marked immunological differences between the auto- and allograft groups were noted. CONCLUSIONS: Free auricular cartilage can be used to reconstruct the extensive anterior defect of trachea in both auto- and allo-transplantations.

Animals↗

PubMed2002

[Tissue-engineered auricled cartilage: an experimental study].

OBJECTIVE: To study the feasibility of engineering auricled neocartilage with chitosan/polylacticacid-polycrylactone (PLA-PCL) network scaffolds and to search the difference between dynamic and silent chondrocytal culture techniques. METHODS: Chondrocytes from auricled cartilage of 4 weeks old New Zealand White rabbit were seeded onto chitosan/PLA-PCL network. Ten cell-polymer scaffolds were divided into two groups: dynamic group (n1 = 5) with rotating bioreactors and silent group (n2 = 5) with ordinary dishes to culture. Using scan electroscope, grossly histological and immunohistological techniques, the morphological evaluation was done individually at 1st week in vitro, 4th and 8th week in vivo. RESULTS: Chondrocytes adhered and grew up well on the network, but more quantities of chondrocytes, Glycoaminoglygan (GAG) and type II collagen were found in dynamic group. There was an obvious difference between dynamic and silent group (P < 0.05). CONCLUSION: Chitosan/PLA-PCL network scaffold is good for adhesions and growth of chondrocytes. Furthermore, dynamic cell culture method is better than silent method for formation of neocartilage.

Animals↗