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BACKGROUND:Human hypoxia-inducible factor-1 alpha can regulate the expression of osteogenic and angiogenic genes, and promote osteogenic activity. OBJECTIVE:To observe the expression of osteogenic genes in rat bone marrow mesenchymal stem cells carrying human hypoxia-inducible factor-1 alpha slow virus infection. METHODS:Hypoxia-inducible factor-1 alpha was obtained from Hela cells using RT-PCR. Lentivirus expression vector plasmid carrying hypoxia-inducible factor-1 alpha (Lenti-HIF-1α-eGFP) was constructed. 293Ta cells with LentiPac HIV mixed packaging plasmid was packaged, and then lentivirus was obtained. Rat bone marrow mesenchymal stem cells were isolated and cultured using direct whole bone marrow adherent method. Bone marrow mesenchymal stem cells were identified using flow cytometry. Bone marrow mesenchymal stem cells were infected with slow virus for 1, 4, 7 and 14 days. Bone morphogenetic protein-2, osteocalcin, osteopontin and alkaline phosphatase expression levels were detected in bone marrow mesenchymal stem cells using real-time fluorescent quantitative PCR. RESULTS AND CONCLUSION:Bone marrow mesenchymal stem cells were effectively infected with Lenti-HIF-1α-eGFP. Real-time fluorescent quantitative PCR results revealed that bone morphogenetic protein-2, osteocalcin, osteopontin and alkaline phosphatase began to obviously overexpress from 4 days after infection with Lenti-HIF-1α-eGFP until 14 days. Results suggested that hypoxia-inducible factor-1 alpha could elevate the osteogenic activity of bone marrow mesenchymal stem cells.
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BACKGROUND:The umbilical cord blood is rich of mesenchymal stem cells, which can be used as a new source of seed cells in tissue engineering. OBJECTIVE:To compare two methods for culturing, expanding and purifying the mesenchymal stem cells in vitro isolated from the human umbilical cord blood. METHODS:The ful-term birth cord blood of 40 cases was col ected under sterile conditions with heparin anticoagulation. Ficol density gradient centrifugation was used to isolate the mononuclear cells from the umbilical cord blood. The cases were randomly divided into two groups according to the different culture media. Twenty cases of umbilical cord blood were cultured in MesenGro human mesenchymal stem cells culture medium (group A), and the remaining 20 cases of umbilical cord blood were cultured in Dulbecco’s modified Eagle’s medium (group B). The occurrence time of fusiform mesenchymal stem cells and cell colony, culture time and the number of primary cells in the two groups were compared. Cells which grew well were selected to detect the surface markers by flow cytometry. RESULTS AND CONCLUSION: The mean occurrence time of fusiform mesenchymal stem cells and cell colony, culture time and number of primary cells in group A were better than those in group B (P < 0.01). The strong expression of the surface markers of mesenchymal stem cells (CD73 and CD105) was found by flow cytometry, of which the positive rate was 99.1%. No expression of the surface markers of hematopoietic stem cells (CD45 and CD34) was seen, of which the negative rate was 99.3%. The number, morphology, growth rate and culture time of umbilical cord blood mesenchymal stem cells cultured in MesenGro human mesenchymal stem cells culture medium were better than those cultured in Dulbecco’s modified Eagle’s medium. Cells cultured in MesenGro human mesenchymal stem cell culture medium can better express surface markers of mesenchymal stem cells.
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BACKGROUND:Nano-hydroxyapatite helps to improve the mechanical properties of bone implants. OBJECTIVE:To study the clinical effect of nano-hydroxyapatite artificial bone on col apsed fracture of the tibial plateau. METHODS:Fourteen cases of col apsed fracture of the tibial plateau combined with bone defects from March 2010 to September 2012 were analyzed retrospectively. The bone defect range was from 1.5 cm×1.0 cm to 3.1 cm×4.5 cm. Al patients were treated with nano-hydroxyapatite artificial bone at an implant amount of 5-14 g. Clinical and X-ray observations were applied at 1 week, 1 month and 3 months postoperatively. Hospital for Special Surgery scores were employed for recovery of knee function. RESULTS AND CONCLUSION:The patients were fol owed up for 12-27 months. Except for one case of a smal amount of wound exudates, no general side effects occurred in 13 cases. X-ray photo showed an integrity interface between nano-hydroxyapatite artificial bone and host bone at 3 months after treatment. Primary healing was obtained in al cases without any complications. Hospital for Special Surgery score was increased to (88.7±4.3) points at 1 year later. These findings indicate that the nano-hydroxyapatite artificial bone has a good biocompatibility and biomechanics, and it may be an ideal artificial bone for repairing col apsed fractures of the tibial plateau.
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BACKGROUND: The free border of meniscus is avascular portion, for which, it is not susceptible for the meniscus to be cured naturally after injury. Therefore, it is necessary to induce fibrous tissue healing probably under certain situation.OBJECTIVE: To adopt tissue engineered cartilage and fibrin adhesive to treat meniscus injury in avascular portion and compare the results.DESIGN: Randomized group division and blank control experiment was designed.SETTING: Animal Laboratory of a Shenzhen Second People's Hospital.green-purplish-blue adult rabbits were selected, randomized into 3 groups,12 rabbits in each, named blank control, fibrin adhesive group(FA group)and tissue engineered cartilage group(TE-C group).METHODS: The experiment was performed in Animal Laboratory of Shenzhen Second People's Hospital from September 2003 to March 2004.Ten baby rabbits borne in 3 to 5 days were sacrificed to collect fibrochondrocytes for culture so as to prepare tissue engineered cartilage containing 12 × 108 L-1chondrocytes. Thirty-six adult rabbits were prepared into the injured model in avascular portion of meniscus (0. 7 × 0. 3) cm with full-thickness laceration. In blank control, no any filler was applied for management; in FA group, fibrin adhesive was infused in laceration; and in TE-C group, tissue engineered cartilage was infused in laceration. Four animals of each of 3 groups were sacrificed in the 2nd, 6th and 12th weeks after operation. Eight menisci were collected in each group each time for gross morphological observation and histological examination.MAIN OUTCOME MEASURES: Gross morphological observation and histological examination in injured meniscus model of rabbit.logical observation in injured meniscus model of rabbit: In blank control, the splits in meniscus were not been healed and tissue filler was not apparent. In FA and TE-C groups, the splits had been filled up with tissue fillers comblank control, 2 to 12 weeks after operation, there was chondrocyte proliferation presented on the border of splits. In FA group, 12 weeks after operation, on the defect border, there were many fibroblastic cells that closely adhered to adjacent tissue, resulting in scar tissue healing. In TE-C group,12 weeks after operation, cartilage cavities and capsule were apparent in the defect and chondrocftes were in cell condensation.CONCLUSION: Tissue engineered cartilage is survived in the acceptors, resulting in fibrocartilaginous healing and specific biological label of chondrocytes. But the remarkable difference presents in collagen arrangement among the repaired tissue, adjacent normal meniscus tissue and normal cartilage.
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Objective To study the feasibility of applying nanometer ceramics artificial bone in clinical repair of bone defects. Methods The animal models of bone defect was made on the unilateral radius of 45 New Zealand white rabbits, which were divided into experimental group(repair with nanometer ceramics artificial bone), control group (repair with ceramics artificial bone) and blank group (unrepaired) randomly. The reconstructive effect in each group was evaluated by gross observation, alkaline phosphatase(ALP) detection of blood serum, histopathological observation, X-ray examination and SEM detection at 4th, 8th and 12th weeks postoperatively. Results In the experimental group there was more bone formation than in the control and the blank groups. The differences in reconstructive effect were statistically significant ( P
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Objective To study the clinical outcome of thoracolumbar fractures treated by ante rior route decompression,bone-graft-fusion and internal fixation.Methods 51cases of thoracolumbar fractures from Jun1994to Mar 2002were treated by anterior route decompression,bone-graft-fusion and internal fixation,of w hich32cases by Kaneda system and 19cases by Z-Plate system.Their clinical data were analyzed.Results The patients were followed up from five months to eight years(average of 3.5years).45cases had a good anatomic reduction and maintain thoracic-lu mbar lordosis.48cases gained one to three Frankel grades of neurologic r e-covery as a consequence of operation.Conclusion Kaneda internal fixation has the characteristics of low cost,neurological decompression and reliable fixation;and Z-Plate systems has the advantages of simple manipul ation,intrinsic stability,less complications and good biocompatibility.
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Objective To report the clinic experience of tr eatment of severe pelvic fracture in order to improve the early diagnosis and operation of the injury.Methods We retrospectively studied the clin ic data of106patients admitted to our hospita l for severe pelvic fracture from Apr il 1994to May 2002.Results The main causes for pelvic fracture were traffic accident injury(69cases,65.1%)and falling accident injury(31cases,29.3%).87cases were in the survival group,and 19cases in the death group,with t he mortality of about 17.9%.In the death group,10di ed from hemorrhagic shock,4of severe cerebral injury,3from MOF,and 2from ARDS.32cases with pelvic f ractures were treated by opening red uction and internal fixation,91.7%of which achieved good results.Conclusion In the treatment of severe pelvic fra ctures,prehospital emergency care is very important.Complicated severe injuries should be treated pr omptly and pelvic fractures be fixed with internal fixation as soon as possibl e.
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Objective To investigate the culture conditions of bone marrow stromal cells(MSCs) to form the tissue engineering cartilage. Methods The MSCs were obtained by the method of primary and passage culture in vitro.Chondrocytes derived from MSCs were obtained with high initial cell density subculture.The cells were cultured and transferred to the 3rd generation,and mixed with fibrin sealing(FS,5?10~6cells/ml).The conformation and growing feature of the tissue engineering cartilage were observed.Results The cultivated MSCs had shown evident reproductive activity and high rate of adherence.The histological results showed that cartilage matrix was stained positively for toluidine blue.Conclusion Chondrocytes can be derived from MSCs and form into the tissue engineering cartilage with FS.