Osteogenic effect and mechanism of IL‐10 in diabetic rat jaw defect mode

Abstract Objective The aim of this study was to investigate the effect of IL‐10 on the phenotype polarization of macrophages and osteogenesis in diabetes mellitus type 2 (T2DM) rat jaw defects. Methods Lipopolysaccharide (LPS) and interleukin‐10 (IL‐10) were chosen to induce the polarization of macrophages. In vitro assessment included wound‐healing assay, western blotting, and alizarin red staining after co‐culture of the bone marrow‐derived mesenchymal stem cells (BMSCs) and induced macrophages. For in vivo study, IL‐10 was loaded on GelMA‐Heparin and applied to bone defects of the alveolar ridge in diabetic rats, while Bio‐Oss Collagen, simple GelMA‐Heparin, and blank control groups were set for contrast experiment. The mandibles of rats were processed for micro‐computed tomography, histology, and immunohistochemistry 1 week and 4 weeks after the operation. Results IL‐10 induced expression of arginase 1, TGF‐β1, EGR2, and Mannose Receptor (CD206), whereas LPS induced expression of iNOS, TNF‐α, IL‐6, CD80. The BMSCs co‐cultured with macrophages induced by IL‐10 showed increased migration, osteogenic differentiation, and mineralization in vitro. Notably, the IL‐10‐laden GelMA‐Heparin group showed quicker new bone formation and a higher M2/M1 ratio of macrophages in the jawbone defect area compared with the control groups. Conclusions IL‐10 can stably induce macrophages to M2 type, thereby influencing BMSCs and improving the osteogenesis of jaw bone defects.