Differential Expression Profiles and Functional Predication of Circular Ribonucleic Acid in Traumatic Spinal Cord Injury of Rats.

Recent studies indicate that circular ribonucleic acids (circRNAs) are involved in a variety of human diseases. The roles of circRNAs in traumatic spinal cord injury (SCI) remain unknown, however. We performed RNA-seq to analyze the circRNA expression profile in rat spinal cord after SCI and to investigate the relevant mechanisms.

Deferoxamine released from poly(lactic-co-glycolic acid) promotes healing of osteoporotic bone defect via enhanced angiogenesis and osteogenesis.

The regeneration capacity of osteoporotic bones is generally lower than that of normal bones. Current methods of osteoporotic bone defect treatment are not always satisfactory. Recent studies demonstrate that activation of the hypoxia inducible factor-1α (HIF-1α) pathway, by genetic methods or hypoxia-mimicking agents, could accelerate bone regeneration.

mTORC1 maintains the tumorigenicity of SSEA-4(+) high-grade osteosarcoma.

Inactivation of p53 and/or Rb pathways restrains osteoblasts from cell-cycle exit and terminal differentiation, which underpins osteosarcoma formation coupled with dedifferentiation. Recently, the level of p-S6K was shown to independently predict the prognosis for osteosarcomas, while the reason behind this is not understood. Here we show that in certain high-grade osteosarcomas, immature SSEA-4(+) tumor cells represent a subset of tumor-initiating cells (TICs) whose pool size is maintained by mTORC1 activity.

Activation of HIFa pathway in mature osteoblasts disrupts the integrity of the osteocyte/canalicular network.

The hypoxia-inducible factors (HIFs), HIF-1α and HIF-2α, are the central mediators of the homeostatic response that enables cells to survive and differentiate in low-oxygen conditions. Previous studies indicated that disruption of the von Hippel-Lindau gene (Vhl) coincides with the activation of HIFα signaling. Here we show that inactivation of Vhl in mature osteoblasts/osteocytes induces their apoptosis and disrupts the cell/canalicular network.

Osteoblast-secreted factors promote proliferation and osteogenic differentiation of bone marrow stromal cells via VEGF/heme-oxygenase-1 pathway.

The hypoxia-inducible factors (HIFα) are the critical factors that couple angiogenesis and osteogenesis by activating transcription of VEGF in osteoblasts. Mice lacking von Hippel-Lindau gene (Vhl), thus overexpressing HIFα in osteoblasts develop extremely dense and highly vascularized long bones. Here we provide evidence that osteoblasts lacking Vhl overexpress and secrete high levels of VEGF, which subsequently promotes the proliferation and osteogenic differentiation of bone marrow stromal cells (BMSC) by promoting expression of Heme oxygenase-1 (HO-1) in BMSC.

Multiple signaling pathways involved in stimulation of osteoblast differentiation by N-methyl-D-aspartate receptors activation in vitro.

Aim: Glutamate receptors are expressed in osteoblastic cells. The present study was undertaken to investigate the mechanisms underlying the stimulation of osteoblast differentiation by N-methyl-D-aspartate (NMDA) receptor activation in vitro.

Methods: Primary culture of osteoblasts was prepared from SD rats.

[Effects of rat serum containing Chinese herbal medicine Sangen Decoction on osteoclastogenesis and bone resorption of osteoclasts induced by polymethylmethacrylate particles].

Objective: To investigate the effects of Sangen Decoction, a compound Chinese herbal medicine, on osteoclastogenesis and bone resorption function of osteoclasts induced by polymethylmethacrylate particles in vitro.

Methods: Macrophage colony stimulating factor (M-CSF) and receptor activator of nuclear factor-κB ligand (RANKL) were used to induce differentiation of bone marrow-derived macrophages (BMMs) towards osteoclasts. BMMs and polymethylmethacrylate particles with ratio of 1:3 were added to the 24-well plate and 96-well plate with bone slices respectively.

[In vitro and in vivo study of chondrogenesis on the hybrid scaffold from fibrin modified PLGA and adipose-derived stem cells].

Aim: To investigated the effect of the presence of fibrin in the PLGA scaffold on the differentiation of adipose-derived stem cell (ASCs) into chondrocytes in the chondrogenic media.

Methods: ASCs were prepared by colagenase I digestion of fat from rabbits. The PLGA scaffolds were prepared by LDM technology.

Biomechanical effects of the Coflex implantation on the lumbar spine. A nonlinear finite element analysis.

Objective: To evaluate the effect of the stabilization of the Coflex device on the biomechanical behavior of the instrumented and adjacent spinal segments.

Methods: The study was carried out at the Department of Orthopedics, Shanghai Institute of Traumatology and Orthopedics, Ruijin Hospital, Shanghai, China between September 2009 and May 2010. Upon validation, a finite element model of L3-S1 segment was developed to simulate and analyze the biomechanics of the intact and Coflex implanted states subjected to simulate loading of flexion, extension, lateral bending, and axial rotation.

Effect of erythropoietin on the survival of retinal neurocytes in culture upon serum withdrawal.

Objectives: To clarify whether erythropoietin (EPO) could substitute for the serum component in cultured retinal neurocytes suffering from serum withdrawal.

Methods: The study was performed in the Shanghai Institute of Traumatology and Orthopedics, Shanghai, China between April 2008 and March 2009. A total of 160 postnatal 2-3 day-old Sprague-Dawley rats were used for this study.

[Expression of hypoxia inducible factor-1alpha in long bone development].

Objective: To observe dynamically the development of fetal long bone and detect the expression and distribution of HIF-1alpha,to investigate the expression pattern and possible effects of hypoxia inducible factor-1alpha (HIF-1alpha) in fetal long bone development of mouse.

Methods: E12.5, E13.

Prolyl hydroxylase inhibitors increase neoangiogenesis and callus formation following femur fracture in mice.

Skeletal trauma and impaired skeletal healing is commonly associated with diminished vascularity. Hypoxia inducible factor alpha (HIF-1) is a key transcription factor responsible for activating angiogenic factors during development and tissue repair. Small molecule inhibitors of the prolyl hydroxylase enzyme (PHD), the key enzyme responsible for degrading HIF-1, have been shown to activate HIF-1, and are effective in inducing angiogenesis.

NMDA enhances stretching-induced differentiation of osteoblasts through the ERK1/2 signaling pathway.

Activation of the excitatory neurotransmitter N-methyl-d-aspartate (NMDA) and stretching both increase Ca(2+) influx in osteoblastic cells. We postulated that NMDA would enhance the osteoblastic cell's response to stretching. The goal of this study was to investigate, in the presence of the neurotransmitter NMDA, the effect of mechanical loading on osteoblast's stage of differentiation and the mitogen-activated protein kinase (MAPK) signaling pathway associated with it.

[Regulation of hypoxia inducible factor-1alpha on osteoblast function in osteogenesis].

Objective: To explore the regulation of hypoxia inducible factor-1alpha (HIF-1alpha) on osteoblast function in osteogenesis.

Methods: Skull-cap bone of HIF-1alpha Loxp/Loxp and VHL Loxp/Loxp C57/BL6 mice were taken out and cultured so as to obtain osteoblasts which were infected with the recombinant adenovirus Ad-Cre so as to conditionally knock out the HIF-1alpha gene and its up-stream gene for von Hippel-Lindau disease (VHL) using Cre-Loxp recombinase technique. Then the osteoblasts were cultured under 2% O2 for 48 hours.

[Experimental study of core binding factor a1 gene-modified rabbit skin fibroblasts enhance bone defect repair].

Objective: To investigate bone defect healing by true bone ceramic complex carrying core binding factor a1 (Cbfa1) gene modified rabbit skin fibroblasts.

Methods: Transfect rabbit skin fibroblasts (RSF) with both eukaryotic expression vector pSG5 which could express Cbfa1 gene and pSG5. After being cultured for 48 h, the transfected RSF were seeded into true bone ceramic (TBC) of 2 cm in length and 4 mm in diameter to construct pSG5-Cbfa1/RSF/TBC complex and pSG5/RSF/TBC complex.

Hypoxia regulation of facilitated glucose transporter-1 and glucose transporter-3 in mouse chondrocytes mediated by HIF-1alpha.

Objectives: Chondrocytes reside in a hypoxic environment; they utilize glucose as the main energy source. Facilitated glucose transport represents the first rate-limiting step in glucose metabolism.

Results: Here we demonstrated that hypoxia induced an elevated expression level of GLUT-1 and -3 in chondrocytes.

[Expression of hypoxia inducible factor-1alpha in the fetal vertebra development: experiment with mice].

Objective: To explore the expression pattern and effects of hypoxia inducible factor-1alpha (HIF-1alpha) in the fetal vertebra development.

Methods: Fetuses at different developmental stages were obtained from C57BL6 mice. The vertebrae of the fetuses were isolated and the development of vertebra was observed by stereoscopic and light microscope.

[Experiment on induction of fibroblasts on 3-D cell-foam structures to express osteoblastic phenotype and its mechanism].

Objective: To study the feasibility of osteogenic phenotype expression by human skin fibroblasts induced in polyglycolic acid (PGA) foams and the effect of tumor necrosis factor-alpha (TNF-alpha) on the expression of bone morphogenetic protein (BMP) receptors.

Methods: The fibroblasts were isolated, purified from human skin. (1) Fibroblasts were seeded onto PGA foams.

[Experimental study on the osseointegration of nanophase hydroxyapatite biograde-coated implants].

Objective: To study the osseointegration of the nanophase hydroxyapatite biograde-coated implants and host bone.

Methods: Nanophase hydroxyapatite biograde-coated implants, hydroxyapatite biograde-coated implants and noncoated Ti-6Al-4V implants were inserted into both femoral of Beagle canines the tissue response, dynamic osteogensis and SEM were studied at 4, 8 and 12 weeks.

Results: The degradation of nanophase hydroxyapatite was slower than hydroxyapatite, dynamic osteogensis and the form of osteoblast were better than the control groups.

[Cbfal's effect on chondrogenic gene expression in fibroblast].

Objective: Core-binding factor a1, Cbfa1, which belongs to the runt-domain gene family, is an essential transcription factor for osteoblastic differentiation and osteogenesis. To examine the effects of Cbfa1 exhibit on gene expression which involving in the chondrogenesis.

Methods: On the first, using RT-PCR method, we directly cloned Cbfa1/Runx2 full length cDNA from E13.

[Osteogenesis of rabbit skin fibroblast transfected with core binding factor a1/osteoblast specific transplanting factor-2 gene].

Objective: To study osteoblastic phenotype expression of New Zealand rabbit skin fibroblasts transfected with mouse core binding factor a1/osteoblast specific transplanting factor-2 gene (Cbfa1/Osf2).

Methods: Cbfa1/Osf2 gene, engineered into eukaryotic expression vector pSG5, was introduced into New Zealand rabbit skin fibroblasts with catholyte liposomes-Lipofectamine 2000. Meanwhile, those transfected pSG5 and un-transfected were set the control groups.