[Lentivirus-mediated BMP-2 overexpression plasmid transfection into bone marrow mesenchymal stem cells combined with silk fibroin scaffold for osteoblast transformation].

OBJECTIVE: To explore the effect of lentivirus-mediated BMP-2 overexpression plasmid transfection into bone marrow mesenchymal stem cells and silk fibroin scaffold on osteoblast transformation. METHODS: The lentivirus BMP-2 overexpression vector was constructed, bone marrow mesenchymal stem cells were cultured, and the combined culture system of nuclear scaffolds was constructed. Alizarin red staining and alkaline phosphatase staining were used to detect the osteogenic transformation of bone marrow mesenchymal stem cells in vitro. Ten New Zealand white rabbits, weighing 3.2 to 4.5 kg(averaging 3.9 kg), aged (2.89±0.45) years old, were selected to construct the rabbit tibial defect model by drilling a conical tibial defect (5 mm in length, 2 mm in width and 3 mm in depth) with an oral drill. The repair of the tibial defect in the animal model was observed by HE staining. The experimental group was implanted with silk fibroin scaffold + BMP-2 overexpression vector bone marrow mesenchymal stem cell complex, while the negative control group was implanted with silk fibroin scaffold+non-transfected bone marrow mesenchymal stem cell complex. RESULTS: Compared with the control group(silk fibroin scaffold+non-transfected bone marrow mesenchymal stem cells), the number of adherent cells on the surface of the scaffold in the experimental group(silk fibroin scaffold+transfected BMP-2 overexpression vector BMP-2 complex) increased significantly. Compared with the control group, the ECM secretion in the experimental group increased significantly. EDX analysis showed that the content of calcium ion was 0.22% in the control group and 0.86% in the experimental group, which showed that the ability of inducing calcium ion formation in the experimental group was stronger than that in the control group. Alizarin red staining of calcium nodules showed that there was no obvious change in the naked eye of the control group, and a small amount of calcium nodules could be seen under the microscope. In the experimental group, obvious red area staining was observed by naked eye, and a large number of calcium nodules were observed by microscopy. The results of alkaline phosphatase staining showed that there was no obvious change in the naked eye of the control group, and no obvious change in the microscopic observation. In the experimental group, purple area staining was observed by naked eyes, and ALP staining was strongly positive by microscopy. The combined culture system of silk fibroin scaffold and bone marrow mesenchymal stem cells can repair cartilage defects. The repair effect of BMP-2 bone marrow mesenchymal stem cells after transfection is obviously better than that of non-transfection group. HE staining showed that inflammatory cells decreased and scaffolds disappeared slightly in the control group. In the experimental group, inflammatory cells were significantly reduced, scaffolds disappeared and angiogenesis was observed. CONCLUSIONS: Lentivirus-mediated BMP-2 overexpression plasmid can promote BMSC to differentiate into osteocytes and secrete more extracellular matrix containing Ca²âº to promote bone defect repair.

Three-dimensional (3D) Printing Technology Assisted by Minimally Invasive Surgery for Pubic Rami Fractures.

The feasibility of three-dimensional (3D) printing technology combined with minimally invasive surgery in the treatment of pubic rami fractures was explored. From August 2015 to October 2017, a series of 30 patients who underwent surgical stabilization of their anterior pelvic ring (all utilizing the 3D printing technology) by one surgeon at a single hospital were studied. The minimally invasive incisions were made through anterior inferior cilia spine and pubic nodule. Data collected included the operative duration, the blood loss, the damage of the important tissue, the biographic union and the recovery of the function after the operation. Measurements on inlet and outlet pelvic cardiograph were made immediately post-operation and at all follow-up clinic visits. The scores of reduction and function were measured during follow-up. Results showed that the wounds of 30 patients were healed in the first stage, and there was no injury of important structures such as blood vessels and nerves. According to the Matta criteria, excellent effectiveness was obtained in 22 cases and good in 8 cases. According to the functional evaluation criteria of Majeed, excellent effectiveness was obtained in 21 cases and good in 9 cases. It was suggested that the 3D printing technology assisted by minimally invasive surgery can better evaluate the pelvic fracture before operation, which was helpful in plate modeling, and can shorten surgery duration and reduce intraoperative blood loss and complications. The positioning accuracy was improved, and better surgical result was finally achieved.

Three-dimensional computed tomography imaging increases the reliability of classification systems for tibial plateau fractures.

OBJECTIVE: The purpose of this study was to determine whether three-dimensional reconstructed computed tomography (CT) images can improve intra-observer and inter-observer reliability for classification systems of tibial plateau fractures compared to plain radiographs and two-dimensional CT images. METHODS: Twenty-one tibial plateau fractures were classified independently by four attending orthopaedic trauma surgeons using the AO/ASIF and Schatzker classification systems. First, a combination of plain radiographs and two-dimensional (2D) CT images were evaluated. Second, 4 weeks later, plain radiographs and three-dimensional (3D) CT images were assessed. Then, 4 weeks later, these two rounds of evaluation were repeated. The intra-observer and inter-observer reliability were assessed using kappa statistics. RESULTS: Three-dimensional CT images can improve the inter-observer and intra-observer reliability regarding both AO/ASIF and Schatzker classification systems of tibial plateau fractures compared to 2D CT images. The degree of agreement of the inter-observer and intra-observer reliability among four surgeons increased from 'substantial' to 'almost perfect'. CONCLUSION: Three-dimensional CT is a more reliable radiographic modality than 2D CT in evaluation of fracture patterns in tibial plateau fractures. This finding seems to show that more sophisticated imaging techniques can improve the reliability of fracture classification systems.