Abstract:Objective To investigate the effect of isoquercetin on bone fracture healing in rats by promoting bone marrow mesenchymal stem cell migration and osteogenic differentiation. Methods CCK-8 was used to detect the proliferation of bone marrow mesenchymal stem cells (BMSCs). Transwell assay was used to detect the migration of BMSCs. Alizarin Red S staining was used to detect calcium deposition in BMSCs. Alkaline phosphatase (ALP) detection kit Detection of ALP activity in BMSCs. Western blotting was used to detect the protein expression of Runx2 and OCN. 40 fracture SD rats were randomly divided into control group, BMSC group, isoquercetin group and BMSC+isoquercetin group, ten rats in each group. Rats in the control group were injected with PBS in the tail vein and intraperitoneal cavity, rats in the BMSC group were injected with 2×106 BMSCs in the tail vein, PBS was injected intraperitoneally, and rats in the isoquercetin group were injected intraperitoneally with 40 mg / kg isoquercetin and PBS in the tail vein. In the BMSC+isoquercetin group, 2×106 BMSCs were injected into the tail vein, and 40 mg / kg isoquercetin was injected intraperitoneally. The fractures of rats were detected by Xray photography; and the expression of OCN and ColⅠ in the callus was detected by immunohistochemistry. Results Compared with the control group, isoquercetin (5μmol/L, 10μmol/L, and 20μmol/L) promoted BMSCs proliferation, of which 10μmol/L had the most obvious effect (P<0.05). Compared with the control group, isoquercetin (5μmol/L and 10μmol/L) promoted BMSCs. Migration, calcium deposition and ALP activity promoted Runx2 and OCN protein expression in BMSCs (P<0.05). In vivo experiments, compared with the control group or the BMSC group, the rats in the BMSC+isoquercetin group had fracture healing scores, expressions of OCN, and ColⅠ increased after 2 weeks of fracture (P<0.05). There was no significant difference between the BMSC group and the isoquercetin group compared with the control group (P>0.05). Compared with the control group, rats in the BMSC group, the isoquercetin group, and the BMSC+isoquercetin group had a fracture healing score increased after 3 weeks of fracture, and the expressions of OCN and ColⅠ increased (P<0.01). Compared with the BMSC group, in the BMSC+isoquercetin group, the fracture healing score increased and the expressions of OCN and ColⅠ increased after 3 weeks (P<0.05). Conclusion Isoquercitrin promotes bone fracture healing in rats by promoting bone marrow mesenchymal stem cell migration and osteogenic differentiation in rats.