Sun, et al. reported that successful preparation of 3D bio-printed scaffolds loaded with macrophages and BMSCs, the inflammatory response was inhibited and the secretion of BMP-2 by macrophages was facilitated by inducing the polarization of macrophages to M2 macrophages, thus further accelerating the bone repair of diabetic bone defects (Sun X. et al., 2021), which in line with our results of immunohistochemical staining. Here, BMP2 is linked to diabetes mellitus.