The Mechanism Of Injectable Mxene Hydrogel Regulating BMP Pathway To Induce Heterotopic Ossification Of Intervertebral Disc

Objective It presents a new fusion-promoting treatment approach for percutaneous endoscopic lumbar fusion by designing and synthesizing injectable MXene hydrogel and using the material features of MXene hydrogel to induce heterotopic ossification under the control of the BMP signaling system.Methods 1.Material synthesis: combine gelatin and methacrylate(MA)in PBS buffer Mix and execute constant temperature dialysis.Freeze-dry the dialyzed liquid at-80 °C to generate porous foam samples for storage.2.Molecular level test: RNA extraction,real-time quantitative PCR,and Western Blot protein quantitative analysis were performed on the annulus fibrosus cells and stem cells in co-culture with MXene hydrogel materials.The expression of alkaline phosphatase(ALP),bone morphogenetic protein 2(BMP2),osteopontin(OPN),and osteocalcin(OCN)was also measured to confirm the material’s impact on the differentiation of the fibrous annulus.3.Cell level test: Mouse osteoblasts were co cultured with MXene hydrogel,and apoptosis was detected by CCK-8 cell staining and cytoskeleton fluorescence staining to study the cytotoxicity and biological safety of MXene in hydrogel at different concentrations.4.Animal level experiment: After creating a rat animal model of a fibrous ring defect using spinal surgery,the MXene hydrogel is injected and cured with UV irradiation.The experimental animals were exposed to Micro CT examinations at 8,and 12 weeks after starting treatment.Then create a 3D model using image processing tools.Result 1.Mxene hydrogel material developed successfully and with the right stiffness.2.The CCK-8 reagent test revealed that when the culture time and Mxene concentration grew,the absorbance steadily increased.3.ALP staining showed that with the extension of co culture time with Mxene hydrogel,the gray and blue precipitates produced by staining became more and more dense,that is,the ALP activity was higher.4.Alizarin S staining reveals that the red mineralized nodules created by staining are more numerous and dense,indicating that osteoblasts are differentiating,the longer the coculture time with MXene hydrogel is.5.The results of the q RT-PCR experiment demonstrated that the expression of BMP pathway-related genes BMP-2,Col1α1,OPN,and Ocn was upregulated to varying degrees in the experimental group,and the difference was statistically significant compared with the control group(p<0.05).6.Western blot showed that the levels of BMP pathway related proteins BMP-2、Col1α1 、OPN and Ocn in the experimental group increased in different degrees,and the difference was statistically significant compared with the control group(p<0.05).7.The rat intervertebral space defect model experiment demonstrated that ossification signals could be detected in an MRI examination 8 weeks after the implantation of MXene hydrogel in the rat intervertebral disc defect,and overt signs of ossification and intervertebral space fusion could be detected 12 weeks later.Conclusion By triggering the BMP signaling pathway,MXene hydrogel,which has good biocompatibility and the capacity to stimulate cell growth,can stimulate osteoblast differentiation and proliferation.