Objective　To explore the influence of stress-relaxation plate(SRP) fixation on the remodeling of cortex under plate. Methods　Twenty-eight New Zealand rabbits were used in this study, the bilateral tibia were osteotomized in the middle and fixed with SRP (experimental group) and rigid plate (control group) respectively. The scanning electron microscopy was used to observe the bone remodeling process from 2 to 48 weeks after operation. Results　There was cortex osteoporosis beneath plate in different degree in both experimental and control groups before 8 weeks, it showed as the disorganization of collagen fiber structure and formation of resorption cavities. In comparison, the osteoporosis degree in experimental group showed milder than that of the control group. After 12 weeks, the resorption cavities became smaller, and the structure of collagen fibers became regular with the alignment parallel to the long axis of cortex. In contrast to the experimental group, the bone osteoporosis under plate of control group exacerbated continuously. Conclusion　Without removal of the bone plate, SRP fixation not only reduce the degree of plated bone osteoporosis, but also make the osteoporosic bone return to normal.

[Objective]In present study an in vivo wear particles induced mouse calvarial osteolysis model was used to investigate the inhibitory effect of erythromycin over wear particles induced osteolysis.[Method]Twenty-four male eight-week-old C57BL/J6 mice were allocated into 4 groups: PMMA group receiving 30 mg PMMA particles implantation onto the calvariae,PMMA+2EM group receiving 30 mg PMMA particles implantation and EM 2mg/kg ip injection,PMMA+10EM group receiving 30 mg PMMA particles implantation and EM 10mg/kg ip injection,control group receiving sham operation.Seven days later,mice calvariae were harvested for pathology analysis.[Result]Middle suture area in the control group was 0.079 mm2?0.011 mm2,in PMMA group 0.335 mm2?0.129 mm2.In PMMA+2EM group the area was 0.094 mm2?0.019 mm2,PMMA+10EM group was 0.091 mm2?0.028 mm2.Osteoclasts number in osteolysis area in the control group were 5.3?1.0,in PMMA group 19.2?5.3,PMMA+2EM group was 6.6?1.1,PMMA+10EM group 6.1?1.9.Compared with control group,PMMA particles induced significant osteolysis(P

ObjectiveTo study the influence of stress－ relaxation plate on disorganization andrepair of the cortex under the plate. MethodsA washer made of viscoelastic polyethylene was placedbetween the screw and the screw hole of a conventional stainless rigid plate(RP) to form a stress－ relax-ation plate(SRP). Both SRP and RP were applied to the osteotomized New Zealand rabbit tibia, thefracture healing process of either fixing with SRP or RP(control) was put under comparative study bypolarized light microscopy, in situ hybridization of collagen mRNA and immunohistochemistry tech-nique from 2 to 36 weeks postoperatively. ResultsThe study of plated bone remodeling showed thatthe degree of cortex osteoporosis beneath the plate was similar between the SRP and RP group 12 － weekpostoperatively. The organization of the bone structure in the SRP group happened later and milder thanthat of the RP group, and the repair process began 12 weeks after implantation. So the resorption cavi-ties became smaller and the structure of collagen fibers became well oriented along, and the osteoblastslying on the surface of resorption cavities expressed and synthesized type Ⅰ collagen 8 to 12 weeks afterimplantation. The changes above increased significantly in most cavities by 36 weeks. No expression andsynthesis of any kind of collagen could be observed during 12 to 36 weeks after implantation in the RPgroup. ConclusionWithout removal of the bone plate, the SRP fixation not only reduces the degreeof plated bone osteoporosis, but also makes the disorganized bone structure return to normal by the ex-pression and synthesis of type Ⅰ collagen mRNA of osteoblasts lying on the surface of resorption cavities.

Objective To explore the effects of alendronate on adipogenic differentiation of bone marrow stremal cells (BMSCs) and the role of mitogen-activated protein kinases (MAPK) signal pathway in this process. Methods BMSCs were derived from 9-month-old ovariectomized SD rats and exposed to 0.01, 0.1, 1, 10 μmol/L of alendronate for 2 weeks. The number of BMSCs was counted under light microscope after oil red O staining. The expression of peroxisome proliferators activated receptor-γ, 2 (PPAR-γ2) was measured by RT-PCR. The effect of alendronate on MAPK signal pathway was detected by Western blot. Results After two weeks of induction of BMSCs by alendronate, BMSCs with positive oil red O staining significantly decreased as the increase of the concentration of alendronate (P <0.01), so did the expression of PPAR-γ2. The expression level of PPAR 2 increased when exposing BMSCs to ERK1/2 or JNK specific inhibitors, PD98059 and SP600125 for two weeks. However, the expression level of PPAR 2 decreased when exposing BMSCs to SB203580 (an inhibitor of p38) for two weeks. Condusion Alendronate can inhibit adipogenic differentiation of BMSCs derived from ovariectomized rats in a doso-dependent manner by activating ERK1/2 and JNK rather than p38.

BACKGROUND: Clinical studies demonstrate that the durable stability of the prosthesis depends on a close geometric fit between the prosthesis and femoral medullary cavity.OBJECTIVE: To study the law of the parameters of medullary canal section shape in proximal femur DESIGN: Repeated measurement observation.SETTING: Department of Orthopaedics, Ninth People's Hospital, School of Medicine, Shanghai Jiaotong University MATERIALS: Ten femoral samples without any damage was obtained from corpse in the Staff Room of Anatomy of the Shanghai Second Medical University METHODS: The experiment was carried out in the Department of Or thopaedics, Ninth People's Hospital between January 2000 and March 2000. Section morphology of medullary cavity of proximal femur was dealt with image-processing, and conus curve fitted parameter mathematical method was proposed; and at the same time, section of medullary cavity of proximal femur of 10 patients was measured manually.MAIN OUTCOME MEASURES: Computer-aided method and manual method were applied to measure the coordination at the end of extrude and the coordinate of link joint RESULTS: 10 femoral samples entered the stage of result analysis. Com puter was used to measure the coordination of the end of extrude of the section medullary cavity of proximal femur (X,Y) and the coordination of the connection point (X,Y).There was no significant difference of the measuring results between computer-aided method and manual CONCLUSION: Computer-aided imaging-processing method not only reduces the error but also can be completed by computer automatically in measuring section morphology of medually cavity in proximal femur. It is suitable for a variety of morphology measurement.

Objective To evaluate effectiveness of bone marrow derived mesenchymal stem cells(BMSCs) transduced by adenovirus mediated human bone morphogenetic protein-2 (Adv-hBMP-2) gene in the repair of diaphysic segmental bone defects of goats. Methods The tibial bone defects (2.1 cm) of 22 goats, who weighted from 18.1 kg to 29.5 kg, were established and divided into 4 groups: groupⅠ, Adv-hBMP-2 transduced BMSCs group (n=8); groupⅡ, adenovirus mediated ?-galactosidase(Adv-?gal)gene transduced BMSCs group (n=6); groupⅢ, non-transduced BMSCs group (n=6); groupⅣ, untreated group (n=2). Roentgenography, histomorphometrical analysis and biomechanical measurement were studied at various times. Results Roentgenography showed more callus in the bone defect site of group Ⅰ. At 24th week after implantation, the healing rates of group Ⅰ,Ⅱ,Ⅲ, and Ⅳ were 6/7, 1/5, 2/5, and 0/1 respectively. There was statistic significant difference of X-ray grading between groupⅠand groupⅡor Ⅲ. Histomorphometrical analysis showed much more total new trabecular bone area (TBA) of groupⅠthan that of other groups. Biomechanical strength of groupⅠwas superior to that of groupⅡand Ⅲ. Conclusion Adenovirus mediated BMP-2 gene transferred BMSCs can repair segmental bone defect in goat without osteoconductive scaffold.

Objective To investigate the rejection mechanisms of bone grafts by comparing the immune reaction of xenografts versus allografts, and the influence of IL-4 and IL-10 on immune responses. Methods Twenty C57BL/6 mice and 1 New Zealand rabbit were used as transplant donors for allografts and xenografts, respectively. One hundred BALB/c mice were used as transplant recipients and randomly divided into 5 groups. Using a model of the muscle pouch for implantation, the immune reactions of bone allografts and bone xenografts were studied through observing the lymphocyte responses of the stimulating index of lymphocytes from the mixed lymphocyte culture (MLC), subsets of lymphocyte, cytokinetic and histological findings in 1, 2, 4 and 6 weeks after implantation respectively. Results Xenograft rejection was rapid (1 week) and stronger than allograft rejection (P

[Objective]To observe the effect of sciatic nerve and femoral nerve resection on heterotopic osteogenesis induced by recombined human bone morphogenetic protein-2(rhBMP-2) and discuss role of never innervation on bone regeneration and partial reasons for larger callus after bone fracture accompanying denervation.[Method]A total of 36 male ICR mice were divided into experimental group and control group at random.0.125mg rhBMP-2 /collagen composites were implanted into the right thigh muscle pouches after sciatic nerve and femoral nerve section in the experimental group and after sham operation in the control group.On the 7~(th),14~(th) and 21~(st) day after implantation,roentgenographic,biochemical,histological analyses and osteoclasts TRAP staining were performed to detect the effects of sciatic nerve and femoral nerve resection on bone growth initiated by rhBMP-2.[Result]On the 7~(th),14~(th) and 21~(st) day,wet weight of new bony tissues of the experimental group was obviously greater than that of the control group.Radiography showed range of bone formation in the experimental group was larger than that in the control,but density of new bone was lower than that of the latter.Biochemical detection showed value of AKP of the experimental group was significantly higher than that of the control on the 7~(th) day,while the content of Ca of the experimental group was higher than that of the control on the 14~(th) day and the content of Ca and P of the experimental group was lower than that of the control on the 21~(st) day.Histological observation showed area of new bone of the experimental group was greater than that of the control,but trabecular bone of the former was sparser than that of the latter.Image analysis of bony tissue showed the relative number of osteoclasts in the experimental group became higher on the 21~(st) day,while volume density and width of bone trabecula in the experimental group were lower than that of the control group.TRAP staining showed osteoclasts in the new bone of the experimental group were more activated than that of the control.[Conclusion]Nerve section results in enhancement of ability of bone regeneration by BMP in the early period,but trabecular bone becomes sparse in the middle and later period because of bone resorption by osteoclasts,which indicates nerve in nervation influences bone regemeration though direct and/or indirect way.

[Objective]To identify the expression of neurotrophic factors(NTFs)and their high affinity receptors(Trk)during the bone induction by recombined human bone morphogenetic protein-2(rhBMP-2)and discuss possible roles of NTFs on the osteoinductive activity of BMP.[Method]After a total of 36 ICR mice were divided into experimental group and control group at random,rhBMP-2/collagen sponge and collagen sponge were implanted into the right thigh muscle pouches of two groups respectively.Tissues in the implanted sites of two groups were removed on the 7~(th),14~(th) and 21~(st) day after implantation.Histological,immunohistochemical and RT-PCR analyses were performed to detect osteoinductive effect of rhBMP-2 and the expression of NTFs and Trk.[Result]RhBMP-2/collagen sponge displayed a potent ability inducing bone formation,while the expression of NTFs and Trk was observed in the course of osteoinduction by rhBMP-2.Especially on the 7~(th) day in the experimental group,NGF and TrkA positive immunostaining reached the peak in the stage of chondrogenesis,including chondroblasts,chondrocytes,hypertrophic chondrocytes and osteoblasts,then decreased in the number of positive cells and the intensity of immunostaining on the 14~(th) and 21~(st) day.BDNF was only observed in chondrocytes and cartilage matrix,and TrkB was expressed in chondroblasts and chondrocytes at the 7~(th) day after implantation.Expression of NT-3 was similar to that of NGF,while TrkC was expressed in chondroblasts and chondrocytes on day 7.Expression level of the mRNA of NTFs peaked at 7 days after the implantation,then decreased,which was nearly coincident with immunohistochemical results.[Conclusion]Many different kinds of cells are induced by rhBMP-2 express NTFs and Trk,which suggests that NTFs may play an important role in the osteogenesis initiated by BMP through direct and indirect pathways.

0.05) but by IL 4 the result was significant(P0.05). Conclusion CTLA4 Ig could remarkably inhibit lymphocyte proliferation in MLC than in MLBSC; and IL 4 could be more effective in MLBSC than in MLC; the result did not show any synergetic effect of CTLA4 Ig+IL 4.