Application of a novel porous tantalum implant in rabbit anterior lumbar spine fusion model: in vitro and in vivo experiments / 中华医学杂志(英文版)

BACKGROUND@#Some porous materials have been developed to enhance biologic fusion of the implants to bone in spine fusion surgeries. However, there are several inherent limitations. In this study, a novel biomedical porous tantalum was applied to in vitro and in vivo experiments to test its biocompatibility and osteocompatibility.@*METHODS@#Bone marrow-derived mesenchymal stem cells (BMSCs) were cultured on porous tantalum implant. Scanning electron microscope (SEM) and Cell Counting Kit-8 assay were used to evaluate the cell toxicity and biocompatibility. Twenty-four rabbits were performed discectomy only (control group), discectomy with autologous bone implanted (autograft group), and discectomy with porous tantalum implanted (tantalum group) at 3 levels: L3-L4, L4-L5, and L5-L6 in random order. All the 24 rabbits were randomly sacrificed at the different post-operative times (2, 4, 6, and 12 months; n = 6 at each time point). Histologic examination and micro-computed tomography scans were done to evaluate the fusion process. Comparison of fusion index scores between groups was analyzed using one-way analysis of variance. Other comparisons of numerical variables between groups were made by Student t test.@*RESULTS@#All rabbits survived and recovered without any symptoms of nerve injury. Radiographic fusion index scores at 12 months post-operatively between autograft and tantalum groups showed no significant difference (2.89 ± 0.32 vs. 2.83 ± 0.38, F = 244.60, P = 0.709). Cell Counting Kit-8 assay showed no significant difference of absorbance values between the leaching liquor group and control group (1.25 ± 0.06 vs. 1.23 ± 0.04, t = -0.644, P = 0.545), which indicated the BMSC proliferation without toxicity. SEM images showed that these cells had irregular shapes with long spindles adhered to the surface of tantalum implant. No implant degradation, wear debris, or osteolysis was observed. Histologic results showed solid fusion in the porous tantalum and autologous bone implanted intervertebral spaces.@*CONCLUSION@#This novel porous tantalum implant showed a good biocompatibility and osteocompatibility, which could be a valid biomaterial for interbody fusion cages.

Effect of tensile stress on human heel skin fibroblast proliferation in vitro / 中国骨伤

<p><b>OBJECTIVE</b>To observe the effect of tensile stress on human heel skin fibroblast proliferation in vitro, providing a theoretical basis for preventing the wound edge skin necrosis and nonunion after calcaneal fracture surgery.</p><p><b>METHODS</b>Fibroblast cells were taken from lateral heel skin of a 40 year-old-man, then cultured and subcultured in vitro. After that, they were divided into three groups: 0 hours group, 6 hours group and 24 hours group and were tested by tensile stress testing. The levels of TGF-β1 and IL-6 in nutrient fluid were measured. Transmission electron microscope and light microscope was applied for observe mitochondria and nucleus.</p><p><b>RESULTS</b>Under 10% of the tensile stress, mitochondria decreased, the levels of TGF-β1 and IL-6 in nutrient fluid were decreased and cell proliferation was inhibited gradually with time increasing.</p><p><b>CONCLUSION</b>The human lateral heel skin in a long-time tensile stress state is an important cause of wound edge skin necrosis and nonunion after calcaneus fracture surgery.</p>

Gene expression of bone mesenehymal stem cells transduced by the lentiviral vector of SOX9 gene knockdown / 中国骨伤

<p><b>OBJECTIVE</b>To construct one lentiviral vector containing mouse SRY-related silencing group--box gene 9 (SOX9) and to transfect murine bone mesenehymal stem cells (mBMSCs) in vitro and observe the expression of target gene.</p><p><b>METHODS</b>RNA inteference target sequence was designed in connectin with mice SOX9 gene sequence. The double strands DNAoligo containing interference sequence were synthesized and cloned into lentivirus vector. The siRNA lentiviral vector with SOX9 gene silencing was constructed and identified, which was transfected into rat bone mesenehymal stem cells. The expression of target gene was detected by immunofluorescence, RT-PCR and Western blot.</p><p><b>RESULTS</b>Lenti-SOX9-siRNA-EGFP was recombined successfully and transduced efficiently into mBMSCs. The expression of SOX9 gene silencing was confirmed by RT-PCR and Western blot.</p><p><b>CONCLUSION</b>Mouse SOX9 gene silencing by RNA interference and Lentiviral vector can transfected successfully into mBMSCs. Meanwhile,SOX9 gene may be silenced in SOX9 transduced mBMSCs. This will provide target cells for the following study about SOX9 gene respairing cartilage injury.</p>