Academy of Orthopedics

Guangzhou, China

Academy of Orthopedics

Guangzhou, China

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Guo J.-S.,Southern Medical University | Guo J.-S.,Academy of Orthopedics | Qian C.-H.,Southern Medical University | Ling E.-A.,National University of Singapore | Zeng Y.-S.,Sun Yat Sen University
Current Medicinal Chemistry | Year: 2014

Spinal cord injury (SCI) is a common neurologic disorder that results in loss of sensory function and mobility. It is well documented that tissue engineering is a potential therapeutic strategy for treatment of SCI. In this connection, various biomaterials have been explored to meet the needs of SCI tissue engineering and these include natural materials, synthetic biodegradable polymers and synthetic non-degradable polymers. Nanofiber scaffolds are newly emerging biomaterials that have been widely utilized in tissue engineering recently. In comparison to the traditional biomaterials, nanofibers have advantages in topography and porosity, thus mimicking the naturally occurring extracellular matrix. Besides, they exhibit excellent biocompatibility with low immunogenicity, and furthermore they are endowed with properties that help to bridge the lesion cavity or gap, and serve as an effective delivery system for graft cells or therapeutic drugs. This review summarizes some of the unique properties of nanofiber scaffolds which are critical to their potential application in treatment of injured spinal cord. © 2014 Bentham Science Publishers.

Huang M.-J.,Southern Medical University | Huang M.-J.,Academy of Orthopedics | Wang L.,Southern Medical University | Wang L.,Academy of Orthopedics | And 22 more authors.
Annals of the Rheumatic Diseases | Year: 2014

Background: An exogenous supplement of n-3 polyunsaturated fatty acids (PUFAs) has been reported to prevent osteoarthritis (OA) through undefined mechanisms. Objective: This study investigated the effect of alterations in the composition of endogenous PUFAs on OA, and associations of PUFAs with mammalian target of rapamycin complex 1 (mTORC1) signalling, a critical autophagy pathway in fat-1 transgenic (TG) mice. Methods: fat-1 TG and wild-type mice were used to create an OA model by resecting the medial meniscus. The composition of the endogenous PUFAs in mouse tissues was analysed by gas chromatography, and the incidence of OA was evaluated by micro-computed tomography (micro-CT), scanning electron microscopy and histological methods. Additionally, primary chondrocytes were isolated and cultured. The effect of exogenous and endogenous PUFAs on mTORC1 activity and autophagy in chondrocytes was assessed. Results: The composition of endogenous PUFAs of TG mice was optimised both by increased n-3 PUFAs and decreased n-6 PUFAs, which significantly alleviated the articular cartilage destruction and osteophytosis in the OA model (p<0.01), decreased protein expression of matrix metalloproteinase-13 (MMP-13) and ADAMTS-5 (a disintegrin and metalloproteinase with thrombospondin motifs) in the articular cartilage (p<0.01) and reduced chondrocyte number and loss of cartilage extracellular matrix. Both exogenous and endogenous n-3 PUFAs downregulated mTORC1 activity and promoted autophagy in articular chondrocytes. Conversely, mTORC1 pathway activation suppressed autophagy in articular chondrocytes. Conclusions: Enhancement of the synthesis of endogenous n-3 PUFAs from n-6 PUFAs can delay the incidence of OA, probably through inhibition of mTORC1, promotion of autophagy and cell survival in cartilage chondrocytes. Future investigation into the role of the endogenous n-6/n-3 PUFAs composition in OA prevention and treatment is warranted.

Xiao J.-J.,Southern Medical University | Xiao J.-J.,Academy of Orthopedics | Zhao W.-J.,Inner Mongolia Bayannaoer City Hospital | Zhao W.-J.,Inner Mongolia Peoples Hospital | And 13 more authors.
Molecular and Cellular Biochemistry | Year: 2015

Abstract: Many recent studies have suggested that bergapten (BP), a class of native compound with numerous biological activities such as anti-resorptive properties, may exert protective effects against postmenopausal bone loss. However, it remains unknown whether BP regulates or improves the osteogenic function of bone marrow stromal cells (BMSCs) in the treatment and prevention of osteoporosis. In our study, BMSCs were cultured in osteogenic induction medium with the addition of BP for 2 weeks and an ovariectomized mouse model of osteoporosis was used to investigate the anti-resorptive effect of BP by gavage administration for 3 months. The concentrations of BP used were 0.1, 1, and 10 μmol/L in vitro and the gavage dose was 20 mg/kg/d. The result of our study indicated that BP promotes the expression of alkaline phosphatase (ALP) by BMSCs in vitro in a dose-dependent manner, as revealed by ALP staining. Runt-related transcription factor 2 and osteocalcin were up-regulated both in vitro and vivo, while osterix and collagen Iα1, assessed by immunofluorescence and immunohistochemistry, were correspondingly raised in the presence of BP in BMSCs in vitro. In addition, a protective effect of BP against ovariectomy-induced bone loss was found by distal femur micro-CT scanning, with improvements of bone metabolism parameters such as bone mineral density, trabecular number, and trabecular separation. Furthermore, WNT/β-catenin signaling was activated in the presence of BP in BMSCs in osteogenic culture. Finally, BP promoted differentiation of BMSCs into osteoblasts by up-regulation of the WNT/β-catenin pathway. Graphical abstract: [Figure not available: see fulltext.] © 2015, Springer Science+Business Media New York.

Guo Y.,Academy of Orthopedics | Guo Y.,Southern Medical University | Tran R.T.,Pennsylvania State University | Xie D.,Academy of Orthopedics | And 13 more authors.
Journal of Biomedical Materials Research - Part A | Year: 2015

Attempts to replicate native tissue architecture have led to the design of biomimetic scaffolds focused on improving functionality. In this study, biomimetic citrate-based poly (octanediol citrate)-click-hydroxyapatite (POC-Click-HA) scaffolds were developed to simultaneously replicate the compositional and architectural properties of native bone tissue while providing immediate structural support for large segmental defects following implantation. Biphasic scaffolds were fabricated with 70% internal phase porosity and various external phase porosities (between 5 and 50%) to mimic the bimodal distribution of cancellous and cortical bone, respectively. Biphasic POC-Click-HA scaffolds displayed compressive strengths up to 37.45 ± 3.83 MPa, which could be controlled through the external phase porosity. The biphasic scaffolds were also evaluated in vivo for the repair of 10-mm long segmental radial defects in rabbits and compared to scaffolds of uniform porosity as well as autologous bone grafts after 5, 10, and 15 weeks of implantation. The results showed that all POC-Click-HA scaffolds exhibited good biocompatibility and extensive osteointegration with host bone tissue. Biphasic scaffolds significantly enhanced new bone formation with higher bone densities in the initial stages after implantation. Biomechanical and histomorphometric analysis supported a similar outcome with biphasic scaffolds providing increased compression strength, interfacial bone ingrowth, and periosteal remodeling in early time points, but were comparable to all experimental groups after 15 weeks. These results confirm the ability of biphasic scaffold architectures to restore bone tissue and physiological functions in the early stages of recovery, and the potential of citrate-based biomaterials in orthopedic applications. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 772-781, 2015. © 2014 Wiley Periodicals, Inc.

Jie H.,Southern Medical University | Jie H.,Academy of Orthopedics | He Y.,Southern Medical University | He Y.,Academy of Orthopedics | And 13 more authors.
Oncotarget | Year: 2016

Neutrophils play a central role in innate immunity and are rapidly recruited to sites of infection and injury. Neutrophil apoptosis is essential for the successful resolution of inflammation. Necrostatin-1 (Nec-1,methyl-thiohydantoin-tryptophan (MTH-Trp)), is a potent and specific inhibitor of necroptosis[1] (a newly identified type of cell death representing a form of programmed necrosis or regulated non apoptotic cell death) by inhibiting the receptor interacting protein 1(RIP1) kinase. Here we report that Nec-1 specifically induces caspase-dependent neutrophils apoptosis and overrides powerful anti-apoptosis signaling from survival factors such as GM-CSF and LPS. We showed that Nec-1 markedly enhanced the resolution of established neutrophil-dependent inflammation in LPS-induced acute lung injury in mice. We also provided evidence that Nec-1 promoted apoptosis by reducing the expression of the anti-apoptotic protein Mcl-1 and increasing the expression of pro-apoptotic protein Bax. Thus, Nec-1 is not only an inhibitor of necroptosis, but also a promoter of apoptosis, of neutrophils, enhancing the resolution of established inflammation by inducing apoptosis of inflammatory cells. Our results suggest that Nec-1 may have potential roles for the treatment of diseases with increased or persistent inflammatory responses.

Ma Z.-P.,Southern Medical University | Ma Z.-P.,Academy of Orthopedics | Ma Z.-P.,Inner Mongolia University | Liao J.-C.,Southern Medical University | And 5 more authors.
Cell and Tissue Research | Year: 2015

Osteoporosis (OP) often increases the risk of bone fracture and other complications and is a major clinical problem. Previous studies have found that high blood pressure is associated with bone formation abnormalities, resulting in increased calcium loss. We have investigated the effect of the antihypertensive drug benidipine on bone marrow stromal cell (BMSC) differentiation into osteoblasts and bone formation under osteoporotic conditions. We used a combination of in vitro and in vivo approaches to test the hypothesis that benidipine promotes murine BMSC differentiation into osteoblasts. Alkaline phosphatase (ALP), osteocalcin (OCN), runt-related transcription factor 2 (RUNX2), β-catenin, and low-density lipoprotein receptor-related protein 5 (LRP5) protein expression was evaluated in primary femoral BMSCs from C57/BL6 mice cultured under osteogenic conditions for 2 weeks to examine the effects of benidipine. An ovariectomized (OVX) mouse model was used to investigate the effect of benidipine treatment for 3 months in vivo. We found that ALP, OCN, and RUNX2 expression was up-regulated and WNT/β-catenin signaling was enhanced in vitro and in vivo. In OVX mice that were intragastrically administered benidipine, bone parameters (trabecular thickness, bone mineral density, and trabecular number) in the distal femoral metaphysis were significantly increased compared with control OVX mice. Consistently, benidipine promoted BMSC differentiation into osteoblasts and protected against bone loss in OVX mice. Therefore, benidipine might be a suitable candidate for the treatment of patients with postmenopausal osteoporosis and hypertension. © 2015, Springer-Verlag Berlin Heidelberg.

Li X.,Southern Medical University | Li X.,Academy of Orthopedics | Han Y.,Southern Medical University | Han Y.,Academy of Orthopedics | And 14 more authors.
Journal of Cellular and Molecular Medicine | Year: 2016

This study aimed to investigate whether apigenin (API) suppresses arthritis development through the modulation of dendritic cell functions. Bone marrow-derived dendritic cells (BMDCs) were stimulated in vitro with lipopolysaccharide (LPS) and treated with API for 24 hrs; DC functions, including phenotype expressions, cytokine secretion, phagocytosis and chemotaxis, were then investigated. The effects of API on collagen-induced arthritis (CIA) were examined in vivo, and purified DCs from the lymph nodes (LNs) of API-treated CIA mice were analysed for phenotypes and subsets. In in vitro, API efficiently restrained the phenotypic and functional maturation of LPS-stimulated BMDCs while maintaining phagocytotic capabilities. Moreover, API inhibited the chemotactic responses of LPS-stimulated BMDCs, which may be related to the depressive effect on chemokine receptor 4 (CXCR4). In in vivo, API treatment delayed the onset and reduced the severity of arthritis in CIA mice, and diminished secretion of pro-inflammatory cytokines in the serum and supernatants from the LN cells of the CIA mice. Similar to the in vitro findings, the API-treated mice exhibited reduced expression of co-stimulatory molecules and major histocompatibility complex II on DCs. Furthermore, API treatment strongly down-regulated the number of Langerhans cells, but not plasmacytoid DCs (pDCs) in LNs, which may be related to the depressive effect of API on the expression of CXCR4 on DCs of peripheral blood. These data provide new insight into the mechanism of action of API on arthritis and indicate that the inhibition of maturation and migration of DCs by API may contribute to its immunosuppressive effects. © 2016 John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

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