ABSTRACT
OBJECTIVE@#To investigate the feasibility of a dual-crosslinked injectable hydrogel derived from acellular musclar matrix (AMM) for promoting myoblasts proliferation and myogenic differentiation.@*METHODS@#Firstly, hyaluronic acid was oxidized with NaIO 4 and methylated to prepare methacrylamidated oxidized hyaluronic acid (MOHA). Then, AMM obtained by washing enzymatically treated muscle tissue was aminolyzed to prepare aminated AMM (AAMM). MOHA hydrogel and AAMM were crosslinked using Schiff based reaction and UV radiation to prepare a dual-crosslinked MOHA/AAMM injectable hydrogel. Fourier transform infrared spectroscopy (FTIR) was used to characterize MOHA, AAMM, and MOHA/AAMM hydrogels. The injectability of MOHA/AAMM hydrogel were evaluated by manual injection, and the gelation performance was assessed by UV crosslinking. The rheological properties and Young's modulus of the hydrogel were examined through mechanical tests. The degradation rate of the hydrogel was assessed by immersing it in PBS. The active components of the hydrogel were verified using immunofluorescence staining and ELISA assay kits. The promotion of cell proliferation by the hydrogel was tested using live/dead staining and cell counting kit 8 (CCK-8) assays after co-culturing with C2C12 myoblasts for 9 days. The effect of the hydrogel on myogenic differentiation was evaluated by immunofluorescence staining and real time quantitative polymerase chain reaction (RT-qPCR).@*RESULTS@#FTIR spectra confirmed the successful preparation of MOHA/AAMM hydrogel. The hydrogel exhibited good injectability and gelation ability. Compared to MOHA hydrogel, MOHA/AAMM hydrogel exhibited higher viscosity and Young's modulus, a reduced degradation rate, and contained a higher amount of collagen (including collagen type Ⅰ and collagen type Ⅲ) as well as bioactive factors (including epidermal growth factor, fibroblast growth factor 2, vascular endothelial growth factor, and insulin-like growth factor 1). The live/dead cell staining and CCK-8 assay indicated that with prolonged incubation time, there was a significant increase in viable cells and a decrease in dead cells in the C2C12 myoblasts within the MOHA/AAMM hydrogel. Compared with MOHA hydrogel, the difference was significant at each time point ( P<0.05). Immunofluorescence staining and RT-qPCR analysis demonstrated that the deposition of IGF-1 and expression levels of myogenic-related genes (including Myogenin, Troponin T, and myosin heavy chain) in the MOHA/AAMM group were significantly higher than those in the MOHA group ( P<0.05).@*CONCLUSION@#The MOHA/AAMM hydrogel prepared based on AMM can promote myoblasts proliferation and myogenic differentiation, providing a novel dual-crosslinked injectable hydrogel for muscle tissue engineering.
Subject(s)
Hydrogels , Hyaluronic Acid/pharmacology , Vascular Endothelial Growth Factor A/metabolism , Tissue Engineering/methods , Cell Differentiation , Myoblasts/metabolism , Cell ProliferationABSTRACT
BACKGROUND:Transoral ventral release and posterior fusion have predominated in the treatment of irreducible atlantoaxial dislocation, but there is no consistent conclusion on the clinical efficacy. OBJECTIVE:To explore the clinical outcomes of transoral ventral release and posterior fusion and screw/rod implantation in the treatment of irreducible atlantoaxial dislocation. METHODS:A total of 32 patients with irreducible atlantoaxial dislocation undergoing thetransoral ventral release and posterior fusion were selected. After treatment, they received cervical anteroposterior and lateral digital DR and cervical MRI examinations to understand the conditions of nerve compression and bone fusion. The recovery of nerve function was evaluated using Japanese Orthopaedic Association before treatment, 6 months after treatment and during final fol ow-up. RESULTS AND CONCLUSION:Post-treatment, 29 patients were fol owed-up for an average period of 12 months. (1) Al the patients obtained perfect atlantoaxial joint reduction and bone fusion. This achieved reduction and reconstruction of spinal column stability. (2) Spinal compression was obviously lessened after treatment in al patients, and nerve functions were improved to different degrees. Significant differences in Japanese Orthopaedic Association score were detected between 6 months post-treatment, final fol ow-up and pre-treatment (P<0.05). (3) There were no serious intraoperative complications such as spinal cord or vertebral artery injuries. Postoperative complications such as infection or burst were also not found. (4) Imaging evaluation revealed that transoral ventral release and posterior fusion is safe and effective for treatment of irreducible atlantoaxial dislocation.