ABSTRACT
BACKGROUND: Human amniotic mesenchymal stem cells have a wide variety of sources, low immunogenicity, and multilineage differentiation potential. Studies have confirmed that Scleraxis gene can induce human amniotic mesenchymal stem cells to differentiate into ligaments and accelerate tendon-bone healing. OBJECTIVE: To explore whether Scleraxis induces human amniotic mesenchymal stem cells to promote tendon-bone healing in vivo in rabbits, providing new options for clinical treatment of tendon-bone healing. METHODS: The study protocol was approved by the Ethic Committee of the Affiliated Hospital of Zunyi Medical University, and written informed consent was obtained from each puerpera. The healthy full-term maternal placenta was taken and cultured, and human amniotic mesenchymal stem cells were isolated and cultured by trypsin digestion twice. Then the morphology of the cells was observed under an inverted microscope, and the cells were further cultured until the third generation for subsequent experiments. The lentivirus carrying the Scleraxis gene was transfected into human amniotic mesenchymal stem cells in vitro. Expression levels of ligament-related genes were detected by real-time fluorescent quantitative PCR, and the expression levels of related proteins were detected by immunofluorescence. Human amniotic mesenchymal stem cells transfected with Scleraxis gene were injected into the extraarticular tendon-bone model of rats. After 3 months, specimens were taken to observe the tendon-bone healing. RESULTS AND CONCLUSION: (1) Human amniotic mesenchymal stem cells from passage to third generation showed long fusiform and vortex-like adherent growth under the inverted phase contrast microscope. (2) The third-generation human amniotic mesenchymal stem cells expressed green fluorescence after 24 hours of infection with the Scleraxis gene lentivirus, and the fluorescence expression was strong and stable. (3) Cell counting kit-8 findings indicated that lentivirus transfection of Scleraxis gene showed no influence on the cell growth rate. (4) Real-time fluorescent quantitative PCR findings showed that the mRNA expression of Scleraxis and ligament-related genes type I collagen, type III collagen, Fibronectin and Tenascin-C was significantly increased after lentivirus transfection of Scleraxis gene. (5) The results of immunofluorescence showed that the expression levels of ligament-related proteins type I collagen, type III collagen, Fibronectin and Tenascin-C were increased after lentivirus transfection of Scleraxis gene. To conclude, in vivo animal experiments have confirmed that the lentivirus transfection of Scleraxis gene can accelerate the tendon-bone healing of the rabbit extraarticular tendon-bone model.
ABSTRACT
BACKGROUND: Acellular amniotic membrane scaffold is a natural scaffold with good biocompatibility, which has been widely used in tissue engineering. Scleraxis can promote the differentiation of human amniotic mesenchymal stem cells into human ligament cells and promote tendon-bone healing. OBJECTIVE: To explore whether acellular amniotic membrane scaffold combined with human amniotic mesenchymal stem cells transfected with Scleraxis can promote rabbit tendon-bone healing. METHODS: (1) Human amniotic mesenchymal stem cells were isolated and cultured in vitro. After passaged, the cell morphology was observed. (2) The Scleraxis lentivirus was constructed in vitro and then transfected into passage 3 human amniotic mesenchymal stem cells with optimal multiplicity of infection. The transfection efficiency was detected by q-PCR. (3) The acellular amniotic membrane scaffold was prepared by enzymatic digestion. Then the Scleraxis lentivirus-transfected cells were seeded on the acellular amniotic membrane scaffold in vitro. The cell growth on the scaffold was observed by phalloidin staining. (4) The New Zealand white rabbit tendon was covered with the acellular amniotic membrane scaffold combined with human amniotic mesenchymal stem cells transfected with Scleraxis lentivirus, followed by implanted into the bone tunnel. The tendon-bone healing was detected. RESULTS AND CONCLUSION: The passage 3 human amniotic mesenchymal stem cells adhered well. (2) After transfected with Scleraxis lentivirus for 96 hours, stable green fluorescence was observed. The mRNA expression level of Sclerxis was significantly increased, indicating a success transfection. The epithelial cells of the acellular amniotic membrane scaffold disappeared, indicating a relatively complete decellularization. The basal layer remained intact, and the extracellular matrix component still existed. Phalloidin staining results revealed that the cells on the acellular amniotic membrane scaffold were in good adhesion and growth, and the cell proliferation was not affected. Therefore, In vivo experimental results reveal that human acellular amniotic scaffold combined with human amniotic mesenchymal stem cells transfected with Scleraxis lentivirus can promote the tendon-bone healing.
ABSTRACT
BACKGROUND: Unlike bone, cartilage, or muscle, tendon-specific markers are not well established. The purpose of the study was to investigate expression pattern and level of 6 well-known tendon-specific markers, in various human musculoskeletal tissues, tenocytes, and mesenchymal stem cells (MSCs). METHODS: Musculoskeletal tissue samples of tendon, bone, cartilage, nerve, muscle, and fat were obtained from patients undergoing orthopedic surgery. Tenocytes, MSCs from bone marrow, adipose tissue, and umbilical cord were isolated from each tissue and cultured. Six tendon-specific markers, scleraxis (Scx), tenomodulin (TNMD), thrombospondin-4 (TSP-4), tenascin-C (TNC), type I collagen (Col I), and type III collagen (Col III) were investigated in tendon tissue, tenocytes, and MSCs. RESULTS: mRNA levels of 6 tendon-specific markers were significantly higher in tendon tissue that in other connective tissues levels of Scx, TNMD, TSP-4, and Col III immediately decreased after plating tenocytes in culture dishes whereas those of TNC and Col I did not. In comparison with tendon tissue, mRNA levels pattern of Scx, TNMD, and TSP-4 in tenocytes were significantly higher than that in MSCs, but lower than in tendon tissue whereas expression pattern of TNC, Col I and III showed different pattern with each other. CONCLUSION: This study demonstrated that 6 commonly used tendon-specific markers were mainly expressed in tendon tissue, but that expression level and pattern of the tendon-specific markers with respect to kinds of tissues, culture duration of tenocytes and sources of MSCs.