In summary, G9a inhibited the osteogenic potential of T2DM-BMSCs by regulating the LINC00657/miR-204-5p/IGFBP5 axis and UNC0638 reversed DOP by inhibiting G9a/LINC00657/miR-204-5p/IGFBP5 axis (Figure 6D). Here, IGFBP5 is linked to type 2 diabetes mellitus.