Local Injection of Hydrogel-Containing Monotropein on Promoting Bone Repair in Allogeneic Bone Transplantation Mice

HUANG Ziyu; ZENG Bo; GUO Liqiang; FANG Yide; HU Xiaohui; ZHAO Yongjian; ZHAO Dongfeng; WANG Jing; LU Sheng; SUN Yueli; SHI Qi; WANG Yongjun; SHU Bing

Abstract：Objective Based on the role of mesenchymal stem cells(MSCs)in promoting bone repair and transcriptomics analysis,to investigate the effect and mechanism of local injection of monotropein,an effective component of traditional Chinese herb,on bone repair in mice with bone allograft.Methods 8-weeks-old C129J mice were used to prepare graft bone,and male C57BL/6N mice were used to establish a left middle femur bone graft model.The C57BL/6N mice were randomly divided into model group and monotropein group,and CS-Odexhydrogel containing monotropein was locally injected into mice in monotropein group during bone grafting surgery.Specimens were obtained 56 days post-surgery to assess the morphology,bone mineral density,trabecular microstructure and biomechanical properties of repaired bone tissue.7 days after surgery,callus tissue was taken for detecting transcriptomics detection,the proportion of MSCs in total cells,and the expression level of osteogenic and chondrogenic genes of Bone marrow mesenchymal stem cells(BMSCs).Results On 56 days after surgery,compared with the model group,the thickness of trabecular bone in callus tissue of monotropein group was significantly increased(P<0.05),and the separation of trabecular bone was significantly decreased(P<0.05).On 14 days after surgery,compared with the model group,the formation of callus tissue and cartilage matrix in the monotropein group was more significant.Seven days after the surgery,the proportion of MSCs in the total cells in the callus tissue of mice in the monotropein group was significantly higher than that in the model group(P<0.01),and in the process of inducing osteogenesis and chondrogenic differentiation,ALP,Sox9 and other gene expression levels were significantly increased(P<0.01).The results of transcriptomic GO analysis of callus tissue 7 days after surgery suggested that the effects of monotropein on the early bone repair process mainly focused on metabolic process,developmental process and multicellular organ process,etc.KEGG analysis suggested that monotropein has regulatory effects on amino acid and lipid synthesis and metabolism pathways,inflammation related pathways such as tumor necrosis factor and interleukin-17,as well as the interaction between extracellular matrix and receptors and cell signaling pathways.Conclusion Local injection of monotropein in hydrogel can promote the bone repair process of mice with bone allograft,and its mechanism may be related to its regulation of cell metabolism,local immune micro-environment,intercellular and intertissue interactions in callus tissue at the early stage of bone repair.