Search

To investigate the feasibility of repairing bone defect with methods of tissue-engineering and human bone morphogenetic protein-2 (hBMP-2) gene transfection in osteoporotic rats.Twenty-four 6-month-old female Sprague-Dawley rats underwent ovariectomy, while 8 rats received sham-operations. Three months later, bone mesenchymal stem cells (BMSC) harvested from osteoporotic rats were divided into two groups randomly. Experimental group were transfected by recombinant plasmid carrying hBMP-2 gene, and control group left untreated. All BMSC were seeded into coralhydroxyapatite scaffolds. Then the cell/scaffold constructs were implanted into the defect site created in the ramus of mandible of osteoporotic rats respectively.Positive results were confirmed by immunohistochemistry and in situ hybridization in experimental group. New bone formation was found at the margin of the defect treated with the BMSC modified by hBMP-2 gene transfer at 4 weeks after implantation and appeared mature 8 weeks after the treatment. However, the amount of newly formed bone was much less and there was some adipose tissue at defect margins 8 weeks after implantation in control group.The results of this experiment indicate that BMSC-mediated rhBMP-2 gene therapy in conjunction with bone tissue engineering may allow for successful treatment of large bone defects in osteoporosis rats.

To determine the causes and incidence of facial injuries by an epidemiologic retrospective study.A total of 3 958 patients with facial injuries treated at Department of Oral and Maxillofacial Surgery, West China School of Stomatology, Sichuan University from 1955 to 2001 were investigated. Data regarding age, gender, cause of injury, pattern of fracture and associated systemic injuries were reviewed.The male to female ratio of the patients with facial injury was 4.27:1 and 33.4% of patients were aged between 21 and 30 years. The most common cause of injury was traffic accident (30.6%), followed by falls (21.4%) and collision (15.8%). A total of 794 patients (20.1%) showed only soft tissue injuries. 1 100 patients (27.8%) had multiple fractures in facial bones and 2,064 patients (52.1%) had single fracture. The mandibular fracture was most frequently seen, followed by the maxilla and the zygoma. The most common site of mandible fracture was the body (31.2%), followed by the symphysis (22.7%), the condylar (20.5%) and the angle (13.7%). Accompanied injuries to brain and skull happened in 916 patients (23.1%).Bone fractures were more common in hospitalized patients with facial injuries. The numbers and sites of fracture were related to the causes of injuries and anatomic structure of the bone. The brain and skull injuries, the most often and seriously accompanied injuries, would not be neglected.

To isolate and chondro-inductive culture of human adipose tissue-derived stromal cells and to study their heterotopic chondrogenesis by loading them on alginate gel.Liposuction human adipose tissues were minced and digested with collagenase type I. The obtained stromal cells were primarily cultured in BGJb medium for ten days. Secondary harvested cells were cultured in DMEM-F12 medium supplemented with 10%FBS, 6.25 mg/L insulin, 10 mg/L TGF-beta1, 50 mg/L of freshly prepared L-ascorbate for 14 days. After in vitro assay of chondrogenic phenotypes, the cells at density of 10(10)/L were mixed with 1.2% alginate sodium and 102 mmol/L CaCl(2). The cross-linking cell-alginate gel were injected into four BALB/C athymic mice subcutaneously (1 ml for each mouse). Meanwhile, the auto-controls were set by injecting equal dose of simple alginate gel and pure cells in two opposite buttocks of the same mouse subcutaneously. Two mice were sacrificed at fourth and eighth week postoperatively and all samples were removed, fixed, embedded in paraffin and cut into sections of 5 micro m thick. HE staining, Alcian blue and modified Masson's trichrome staining were employed to observe chondrogenesis histologically.Alcian blue and immunocytochemical staining revealed chondroitin sulfate and collagen II in cell matrix after having been chondro-inductive cultured for 14 days. At intervals of fourth and eighth week, heterotopic chondrogenesis is (cartilage formed) within cell-alginate injected sites were found in all mice but negatively in auto-controls. Histologically the hypertrophic chondrocytes were among cartilage matrix in different staining. All alginate gel and solitory cells absorbed within two to three weeks postoperatively in auto-controls.It seems that stromal cells derived from human adipose tissue presents a potential for chondrogenic differentiation.

To investigate the influence of the viability and new bone formation of osteoblasts by the super high molecular weight poly D,L-lactic acid (SHMW-PDLLA).1. The osteoblasts derived from neonatal rat were grown and maintained at steep of SHMW-PDLLA and normal culture medium. The viability and function of the osteoblasts were measured with MTT array. 2. The plate and screws made of SHMW-PDLLA were implanted and fixed at the artificial fractured mandible of dogs. Specimens were gained at 3 and 6 months and examined with macroscopy and SEM.1. There is no significant difference of OD values between the experimental group and the control group (P0.05). The SHMW-PDLLA isn't toxic to osteoblast at 1 week and 2 weeks, and the toxicity is 3% at 3 days. 2. There were a lot of new bone formed between the implanted SHMW-PDLLA plate and bone tissues under SEM.SHMW-PDLLA hasn't pathological influence on the viability and new bone formation of osteoblasts and it is feasible in tissue engineering of bone.