BACKGROUND:Adenovirus, expressing within a limited period, can limit the expression time and amount of target genes that is not conducive to ongoing experiments. Here, we select adenovirus as vectors for genetic recombination with tumor necrosis factor (TNF)-related apoptosis-inducing ligand (Trail) gene fragment.
OBJECTIVE:To explore the construction of recombinant lentiviral vector carrying Trail in rats
METHODS:The Trail gene was obtained:according to GenBank in rat Trail gene sequence (NM_145681.1), we designed the gene specific primers of Trail-Age I-F and Trail-AgeI-R, and used AgeI as enzyme cutting site. PCR was applied to amplify Trail gene from rat cDNA Library and construct recombinant plasmids after cutting Trail gene to be cloned into expression vector GV218 by AgeI. Recombinant plasmids were transfected into 293T cells by Lipofeetamine2000 encapsulated recombinant plasmid and auxiliary packaging carrier. The Trail protein of lentiviral plasmids was expressed. Fol owing virus col ection, we identified virus titer and extracted protein from cells to detect Trail expression by western blot assay.
RESULTS AND CONCLUSION:Screened positive Escherichia coli DH5a competent cells were sequenced with 861 bp, which was consistent with Trail nucleotide sequence in GenBank. After transfection 2 days, virus liquid was col ected and confirmed as recombinant plasmid including Trail gene by PCR and Trail proteins expressed in 293T cells by western blot assay. Hole dilution method and real-time fluorescent quantitative PCR determination showed that the virus titer was 2×109 TU/mL. In this study, recombinant lentiviral vector carrying Trail is successful y constructed by homologous recombination in Escherichia coli.

BACKGROUND:Cytoskeleton plays an important role in the transduction of mechanical signal, and intermittent tensile stress can promote osteogenic differentiation. However, there is no relevant study about the change of cytoskeleton in osteoporosis rat bone marrow mesenchymal stem cells under intermittent tensile stress. OBJECTIVE:To investigate the effects of intermittent tensile stress on the cytoskeleton of osteoporosis rat bone marrow mesenchymal stem cells during osteogenic differentiation. METHODS:Bone marrow mesenchymal stem cells were obtained from osteoporosis rats and cultured in vitro. The 5%, 10%and 15%tensile stress were strained on the bone marrow mesenchymal stem cells through FX-4000T Flexcell. No stress was in the control group. Osteogenic differentiation of bone marrow mesenchymal stem cells was observed through alkaline phosphatase staining, while the change of cytoskeleton was observed by confocal laser scanning microscopy with figures col ected for analysis by Image-ProPlus 6.0 software. The area of cells, ratio of length to width and integrated fluorescence intensity of cytoskeleton protein F-actin were measured. RESULTS AND CONCLUSION:Under tensile stress, bone marrow mesenchymal stem cells from osteoporosis rats arranged in the direction vertical to mechanical stimulation. cells under different tensile stress differentiated towards osteoblasts. The result of alkaline phosphatase staining showed the most significant difference in 10%group, and quite an amount of cells lining lost succession in the 15%group. Under stress, the F-actin filaments were rearranged in paral el accordingly, which showed a reconstruction of cytoskeleton. Imaging analysis indicated that the area of bone marrow mesenchymal stem cells was decreased in 10%and 15%groups (P<0.05) with the increased ratio of length to width (P<0.05), and expression of F-actin increased in5%, 10%, 15%groups (P<0.05) after tensile stress. Under mechanical stimulation, the cytoskeleton of bone marrow mesenchymal stem cells from osteoporosis rats is shown to have corresponding alterations during osteogenic differentiation.

Cells are exposed to mechanical stress, such as fluid shear stress (FSS), mechanical strain, hydrostatic pressure in vivo. FSS is considered to be the most important stress during bone homeostasis and remodeling. At present, most studies are mainly about the FSS effect on osteocytes and osteoblasts. However, the effects of FSS on bone mesenchymal stem cell (BMSCs) are not fully understood. BMSCs are of great significance in bone reconstruction and clinical treatment, so researchers increasingly focus on the response of BMSCs to FSS. The response of BMSCs to FSS depends on the alteration of cytoskeleton, matrix stiffness and elasticity, osteogenic signaling pathways and so on. In this review paper, the recent researches about the mechanotransduction mechanism of FSS, and its effect on differentiation and function of BMSCs are summarized, so as to provide new insights for studying construction of tissue engineered bone and treatment of bone diseases.

Orthodontic treatment is more complicated when both soft and hard tissues must be considered because an impacted maxillary canine has important effects on function and esthetics. Compared with extraction of impacted maxillary canines, exposure followed by orthodontic traction can improve esthetics and better protect the patient's teeth and alveolar bone. Therefore, in order to achieve desirable tooth movement with minimal unexpected complications, a precise diagnosis is indispensable to establish an effective and efficient force system. In this report, we describe the case of a 31-year-old patient who had a labio-palatal horizontally impacted maxillary left canine with a severe occlusal alveolar bone defect and a missing maxillary left first premolar. Herein, with the aid of three-dimensional imaging, sequential traction was performed with a three-directional force device that finally achieved acceptable occlusion by bringing the horizontally impacted maxillary left canine into alignment. The maxillary left canine had normal gingival contours and was surrounded by a substantial amount of regenerated alveolar bone. The 1-year follow-up stability assessment demonstrated that the esthetic and functional outcomes were successful.

Malocclusion,identified by the World Health Organization(WHO)as one of three major oral diseases,profoundly impacts the dental-maxillofacial functions,facial esthetics,and long-term development of～260 million children in China.Beyond its physical manifestations,malocclusion also significantly influences the psycho-social well-being of these children.Timely intervention in malocclusion can foster an environment conducive to dental-maxillofacial development and substantially decrease the incidence of malocclusion or reduce the severity and complexity of malocclusion in the permanent dentition,by mitigating the negative impact of abnormal environmental influences on the growth.Early orthodontic treatment encompasses accurate identification and treatment of dental and maxillofacial morphological and functional abnormalities during various stages of dental-maxillofacial development,ranging from fetal stages to the early permanent dentition phase.From an economic and societal standpoint,the urgency for effective early orthodontic treatments for malocclusions in childhood cannot be overstated,underlining its profound practical and social importance.This consensus paper discusses the characteristics and the detrimental effects of malocclusion in children,emphasizing critical need for early treatment.It elaborates on corresponding core principles and fundamental approaches in early orthodontics,proposing comprehensive guidance for preventive and interceptive orthodontic treatment,serving as a reference for clinicians engaged in early orthodontic treatment.

Vibration represents a micro reciprocating motion of a particle or object along a line or arc relative to a reference position, while the effect of low-magnitude high-frequency vibration (LMHFV) on skeletal system cells is similar to the mechanical stimulation of muscle movement. Bone mesenchymal stem cells (BMSCs), which have been identified as force-sensitive cells, exist in the bone marrows and have the potential of multi-lineage differentiation. Their biological characteristics can change functionally according to the appropriate stimulation in vitro, in order to reach the optimal demand of the stimulation. LMHFV can promote the osteogenic differentiation of BMSCs, therefore, the research on its mechanism can contribute to the application of vibration in the treatment of diseases such as osteoporosis, fracture, osteogenesis imperfecta, obesity as well as the promotion of orthodontic tooth movement. This paper summarizes the recent progress about the effects of vibration on BMSCs stem cells in osteogenesis and the possible mechanisms, so as to provide research ideas and methods for studying the mechanical as well as biological changes of BMSCs under vibration stimulation.

Objective:To explore the application effect of disease-oriented digitalized teaching model in the undergraduate teaching of stomatology.Methods:A total of 34 undergraduate students in clinical medicine from Batch 2018 were selected as the control group 1, 24 undergraduate students in stomatology from Batch 2015 were selected as the control group 2, and 23 undergraduate students in stomatology from Batch 2018 were collected as the experimental group. The two control groups all accepted the traditional teaching mode, and the experimental group accepted the disease-oriented digitalized teaching model. Finally, the teaching effect was evaluated through questionnaire surveys and less difficult oral professional tests. The SPSS 24.0 was used to conduct t test. Results:After accepting this teaching model, students improved their understanding of the concept of "organism" and "disease" ( P<0.05), and they had a positive evaluation of this teaching model. It was found that the tests scores of the experimental group (42.17±1.21) were significantly higher than those of non-dental major students of the same Batch (24.71±1.42) ( P<0.05), with significant differences, while without significant difference between the tests scores of the senior stemmatological students (43.33±1.30) ( P>0.05). Conclusion:This teaching model enables students to establish the concept of "organism" and form a disease-oriented knowledge framework before entering the decentralized professional courses, which may further stimulates the interest of junior students in their majors, and enhances their professional awareness compared with traditional teaching model. It's also a useful exploration for teaching hospitals to conduct teaching activities of junior undergraduates outside the classroom.

As the national key discipline and the initiator of oral and maxillofacial deformity group, the Department of Oral and Maxillofacial Surgery persisted in teaching, designed a novel teaching form combining theoretical knowledge and online software practice according to the characteristics of our discipline and carried out "cloud training" via the National Oral Telemedicine Education Platform. Ten lecturers, 325 theoretical students and 50 practical students were investigated by questionnaire in the present study with questions focusing on the geographical distribution and composition of personnel, etc. The results showed that the online course covered a wide range of students and achieved high acceptance and satisfaction rate. The first online software operation course was conducted in an orderly manner, with timely interaction between teachers and students. The students were able to master the design process skillfully. This "cloud training" has achieved good results, but there are still a series of problems that have yet to be resolved, such as network stalls and protection of intellectual property rights. Under the new form, the exploration and analysis of the new mode of online telemedicine specialist education will provide some practical reference for the National Clinical Research Center for Oral Diseases to carry out online telemedicine teaching in the future.

Extracellular matrix is the main element to provide mechanical clues for cells. The response of stem cells to mechanical signals is mainly achieved through the cytoskeleton. After mechanical signal is transmitted, cytoskeleton can form contractile microfilaments that actively generate tension through reorganization induced by microenvironment changes. The mechanical signals can regulate gene expression through either coupling with the nuclear skeleton directly or being transformed by the second message. Recent studies have proven that cytoskeleton tension has a series of impact on lineage specification, proliferation, differentiation and apoptosis of bone mesenchymal stem cells (BMSCs). BMSCs are of great significance in bone reconstruction and clinical treatment. The possible mechanisms about mechanotransduction and its effects of cytoskeleton tension on osteogenesis of BMSCs after micro-environmental changes were summarized.

Dento-maxillofacial skeletal abnormalities exhibit high incidence rate,complex etiology,severe symptoms,difficult diagnosis and treatment,and lack of early intervention strategies,which is mainly due to insufficient exploration of mechanism research.These diseases are characterized by abnormal morphology,disordered mutual location and impaired function of bones and teeth,including skeletal abnormalities and malocclusion.Among them,maxillofacial bone and dento-periodontal complex are the two core structures,which respectively determine facial aesthetics and occlusal function.As for maxillofacial skeletal abnormalities,mechanism studies on skeletal development and pathogenesis are required for precise prevention and treatment.As for malocclusion,mechanism studies on homeostasis and stress remodeling are required from the perspective of orthodontics.Both mechanism studies can provide basic support for the diagnosis and treatment of dento-maxillofacial skeletal deformities.In this regard,previous studies usually focused on the expression maps of mutated genes and differential factors.In recent years,the development of conditional gene editing techniques,such as Cre-LoxP system,has enabled researchers to intuitively evaluate the function of key genes in a single cell lineage in vivo,helping to advance research on dento-maxillofacial skeletal abnormalities from phenotype level to molecular mechanism level.This review summarizes recent domestic and foreign researches on dento-maxillofacial skeletal abnormalities,as well as recent achievements of the author's team,and systematically proposes a research mode concluded as"One Centre,Two Motives".The centre is dento-maxillofacial skeletal abnormalities.One motive is the development and pathogenic mechanisms of maxillofacial bone,and the other is the homeostasis and remodeling mechanisms of dento-periodontal complex.The research mode aims at systematical study of the pathogenesis and prognosis of diseases to explore potential therapies.Many advanced technologies have contributed to the exploration of"One Centre"through"Two Motives":on the one hand,conditional gene editing models have provided a new strategy for studying the function of key factors in key cells in vivo;on the other hand,inducible conditional gene editing models have supported the precise control of the timeline for interventions after birth.Furthermore,with the help of single-cell sequencing and lineage tracing techniques,researchers have been focusing on tissue-specific stem cells,due to their in situ and characteristic functions.This situation is highly in line with the"One Centre,Two Motives"mode,and is benefit to shed a new insight on the theoretical researches and clinical applications of dento-maxillofacial skeletal abnormalities.The article reviews the"One Centre,Two Motives"mechanism research mode of dento-maxillofacial skeletal abnormalities.