Concentrated growth factors in the repair of a full-thickness condylar cartilage defect in a rabbit / 中国组织工程研究

BACKGROUND: Concentrated growth factors can promote the repair of tissue injuries. Its effect on the repair of condylar cartilage injuries is rarely documented. OBJECTIVE: To investigate the effect of concentrated growth factors on the repair of full-thickness condylar cartilage defects in rabbits. METHODS: Concentrated growth factors were prepared by collecting the venous blood of rabbits. A full-thickness cartilage defect penetrating the subchondral cortex was created at both sides of condyle in rabbits. The experimental side was filled with concentrated growth factors, and the control side healed naturally. The histomorphology was examined at 2, 6 and 12 weeks postoperatively. The degree of cartilage repair was evaluated by the modified Pineda cartilage repair scale. The release rate of concentrated growth factors was measured at different observational times. The study protocol was approved by the Experimental Animal Ethics Committee of Peking University Health Science Center (approval No. LA201809). RESULTS AND CONCLUSION: Fillings of fibrous and cartilage-like tissue in the defect were observed on both of the experimental and the control sides at 2 weeks postoperatively. Toluidine blue was stained homogeneously in the experimental side. Intercellular fibrous tissues with interpenetrating and heterogeneous toluidine blue staining appeared in the control side. At 6 and 12 weeks postoperatively, the repaired cartilage was identified in the experimental side. On the contrary, fibroid tissue hyperplasia was found in the control side, where toluidine blue staining showed no heterochromatin. Based on the modified Pineda cartilage repair score, the mean value of the total score in the experimental side was better than that in the control side at 6 and 12 weeks postoperatively. The difference in the mean value of the total score (P 0.05). ELISA tests showed that insulin-like growth factor 1, transforming growth factor β1, basic fibroblast growth factor, and vascular endothelial growth factor could be released continuously for more than 14 days. The release rates of these cytokines were decreased with time. These results indicate that concentrated growth factors can improve the early repair of full-thickness condylar cartilage defects in rabbits to some extent.

Experimental study of lentiviral vector-mediated bFGF gene transfection on rabbit BMSCs / 天津医药

Objective To observe the effect of lentiviral vector-mediated basic fibroblast growth factor (bFGF) gene transfection on the biological characteristics of rabbit bone marrow stromal cells(BMSCs)under in vitro culture conditions. Methods BMSCs were obtained by density gradient centrifugation and adherence screening. The bFGF gene was transfected into BMSCs by lentiviral vector and divided into bFGF transfection group,empty virus group and untransfected group according to the transfection conditions.After transfection,the morphology,expressions of bFGF mRNA and protein, cell proliferation,cell cycle and alkaline phosphatase(ALP)activity were observed in three groups of cells. Results High density BMSCs were successfully obtained by density gradient centrifugation and adherence screening.After transfection of BMSCs with bFGF gene, the cell morphology showed no significant changes, while the expressions of bFGF mRNA and protein were significantly increased, the cell proliferation curve shifted upward, the proportion of proliferating cells increased,and the activity of ALP was significantly enhanced.There were significant differences between three groups(P<0.05).Conclusion The rabbit bFGF gene is successfully introduced into the BMSCs cultured in vitro by lentiviral vector, and the target gene is stably expressed.The expression of bFGF can promote the proliferation and osteogenic differentiation of BMSCs.

Dynamic study of correspondence of prescription and syndrome system: a system with combination of disease and syndrome, correspondence of prescription and syndrome / 中国中西医结合杂志

By analyzing the present situation and existing problems in the material bases of syndrome and Chinese materia medica, we think that either syndrome or prescription is a complex whole system. Studies of the material bases of syndrome and prescription should be established on the combination of disease and syndrome, following the holistic and dynamic principles. Departure from the holistic principle, separating the syndrome from the prescription, ignoring the dynamic concepts may possibly lose the features and advantages of syndrome typing and Chinese medicine preparations. The metabolomics research bridges the study of prescription and syndrome. It is of great significance in finding out the agreeable point of disease-syndrome-efficacy, establishing a dynamic research method with combination of disease and syndrome, correspondence of prescription and syndrome.

Immuno-inflammatory reaction after myocardial infarction and treatment with Chinese and Western medicine / 中国中西医结合杂志

At present ventricular remodeling (VR) is regarded as the main pathological basis of chronic heart failure after acute myocardial infarction (AMI), and preventing VR after AMI is of great importance for the prevention of heart failure. Previously, it has not been paid enough attention to the role of inflammation and autoimmune injury during the process of VR after AMI. This topic was discussed in the paper and the treating strategies with Chinese and Western medicine were also explored.

Establishment and application of human papillomavirus type 16 pseudovirions neutralization assay / 生物工程学报

Human papillomaviruses (HPV) are causally associated with cervical cancer and genital warts. Lack of permissive and productive cell cultures for HPV has hindered the study of HPV and evaluation of virus-neutralizing antibodies. So generation of infectious virions in vitro is highly desirable. In this report, we got high titer infectious HPV16 pseudovirions by calcium phosphate co-transfection of codon optimized HPV16 capsid genes L1 and L2 and reporter plasmids into 293FT cell line. Electron micrograph indicated that the pseudovirions were morphologically similar with the intact HPV16 virions. To evaluate the feasibility of using the pseudovirions to identify neutralizing monoclonal antibodies (mAbs), pseudovirions were incubated with 2-fold gradient dilution of the well identified mAbs V5, E70, U4 and D9 and then used to infect 293FT cells preplated in 96-well tissue culture plate. The infection of pseudovirions could be inhibited by neutralizing mAbs V5, E70 and U4 that recognize surface conformational epitopes on L1 VLP, but not by mAb D9 that is reactive to a linear epitope buried in VLP, which indicated that the pseudovirions could be used to evaluate the neutralization efficiency of mono- and polyclonal antibodies. The pseudovirions were then employed to identify neutralizing mAbs from 18 mAbs generated previously in our lab, 8 of which were conformational and 10 were linear. PD1 and 3D10, both of which recognized conformational epitopes on L1 VLP, had obviously strong neutralizing efficiency, with the neutralizing titer reached 81,920 and 20,480 respectively, while none of the linear mAbs were neutralizing, which reflected that rare linear mAbs have neutralization activity. The mechanism of PD1 and 3D10 block the infection of HPV16 pseudovirions need to be further studied. The technologies about generation of HPV16 pseudovirions and screening neutralizing mAb in our report are economical and efficient, can be easily used in large scale. They pave the way for rapid and precise evaluation of the protection efficiency of our prophylactic HPV vaccine being developed now.

Mammalian gene-transfer and expression efficiencies of baculovirus bacV-CMV-EGFPA / 生物工程学报

It has been reported that baculoviruses could serve as a new gene-transfer vehicle for mammalian cells. We have previously constructed recombinant baculovirus BacV-CMV-EGFPA and have proven that mammalian cells could be effectively infected by the recombinant baculovirus. In this report, we studied the efficiency of baculovirus to deliver exogenous gene into twenty mammalian cells, including twelve human cell lines (WI-38, Hela, HepG2, 293, PLC/PRF/5, 143B, MCF-7, BGC-223, DMS 114, CNE, Raji, LCL-cm), seven murine cell lines (BNL 1ME A.7R.1, CHO-K1, L-929, JC, PT67, NIH3T3, P815) and one monkey cell line (CV1). Results showed that most mammalian cell lines could be transduced by the recombinant baculovirus, the transduction efficiencies of the human and monkey cell lines were markedly higher than that of murine cell lines, and the transduction efficiencies in adherent culture cell lines higher than that of suspend culture cell lines, implying that the infection efficiency of the baculovirus may be correlative with the organism used and the growth properties of the cell lines. The plasmid pcDNA3. 1-EGFP, which contains the CMV promoter and EGFP reporter gene, was next transfected by LipofectAMINE into a number of mammalian cells, especially those cells that were low in the baculovirus transfection. Results showed that the CMV promoter could effectively direct the expression of the reporter gene in these mammalian cells. Therefore the gene-expression efficiencies in different mammalian cell lines by the recombinant baculovirus which contains the same CMV promoter were dictated by the ability of the baculovirus to enter the cell lines. This study suggested that the recombinant baculovirus vector is more suitable for gene expression in primate adherent culture cells than in murine cells and suspend culture cells.