Polycaprolactone (PCL) is a synthetic biodegradable polymer that has been approved for use as bone graft substitutes. In this study, PCL scaffolds incorporating hydroxyapatite (HAp) particles were fabricated by combined solvent casting and particulate leaching techniques. The average pore dimension was in the range of about 480-500 microm. The porosity, water absorption, and compressive modulus of the scaffold were evaluated. The responses of primary bone cells cultured on the PCL and PCL/HAp scaffolds were examined both in vitro and invivo. In comparison with the cells grown on the PCL scaffold, those cultured on the PCL/HAp counterpart positively expressed the markers of osteogenic differentiation. Cells increased the mRNA expressions of type I collagen and osteocalcin on day 10 and demonstrated a significant increase in calcium deposition. In coherence with the in vitro appearance, histomorphometric analysis in a mouse calvarial model showed a significantly greater amount of new bone formation. The results demonstrated that the prepared PCL/HAp scaffold could be a good candidate as synthetic substitute for bone tissue engineering. (c) 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010.
Major drawbacks of using an autograft are the possibilities of insufficient bony source and patient's morbidity after operation. Bone tissue engineering technology, therefore, has been applied for repairing bony defects. Previous study showed that a novel fabricated 3D-Polycaprolactone/Hydroxyapatite (PCL/HAp) scaffold possessed a good biocompatibility for bone cells. This study aimed to determine the ability of PCL/HAp for supporting cell growth, gene expression, and osteogenic differentiation in three types of mesenchymal stem cells, including bone marrow-derived mesenchymal stem cells (BMSCs), dental pulp stem cells (DPSCs), and adiposed-derived mesenchymal stem cells (ADSCs). These were assessed by cell viability assay (MTT), reverse-transcription polymerase chain reaction (RT-PCR) analysis, alkaline phosphatase activity, and osteogenic differentiation by alizarin red-S staining. The results showed that PCL/HAp scaffold could support growth of all three types of mesenchymal stem cells. In addition, DPSCs with PCL/HAp showed the highest level of calcium deposition compared to other groups. In conclusion, DPSCs exhibited a better compatibility with these scaffolds compared to BMSCs and ADSCs. However, the PCL/HAp could be a good candidate scaffold for all tested mesenchymal stem cells in bone tissue engineering.
SummaryThe non-catalytic region of tyrosine kinase (Nck) is proposed to play an essential role in T cell activation. However, evidence based on functional and biochemical studies has brought into question the critical function of Nck. Therefore, the aim of the present work was to investigate the role of Nck in T cell activation. To study this, the human Jurkat T cell line was used as a model for human T lymphocytes. The short interfering (
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