Background  Patients with type 2 diabetes have abnormal bone metabolism and marked alterations in both bone quality and bone mass of the jaw, which is one of the systemic contributors to periodontitis. Wnt signaling pathway can promote stem cells mineralization and repair bone tissue defects. However, it is still unknown whether the Wnt signaling pathway is involved in the regulation of osteogenic differentiation of bone marrow mesenchymal stem cells in the jaws under the influence of type 2 diabetes.

  Objective  To investigate the effects of type 2 diabetes on the proliferation and differentiation of jaw bone marrow mesenchymal stem cells (JBMMSCs) in rats and the possible mechanisms.

  Methods  The 13-week-old GK rats with random blood glucose≥16.7 mmol/L for two consecutive weeks were selected as the type 2 diabetes group, and Wistar rats of the same weeks of age served as the control group, with 10 rats in each group. Two groups of JBMMSCs were isolated and cultured as the research object by the combination of bone marrow flashing and bone slice digestion under sterile conditions. CCK-8 method was used to detect and analyze the cell’s proliferative ability. The apoptosis ability of cells was assessed by flow cytometry. The expression of genes related to osteogenesis, adipogenesis and Wnt signaling pathway was assessed by qRT-PCR, alkaline phosphatase (ALP) expression was detected by alkaline phosphatase staining, and the difference in calcium nodule formation was compared by alizarin red staining. Oil Red O staining was used to detect lipid droplet formation differences after lipogenesis induction.

  Results  Compared with the control group, the proliferation and clonogenic ability of JBMMSCs in the type 2 diabetes group decreased, and the proportion of cells of early and late apoptosis increased (P<0.05). Osteogenesis-related genes ALP, OCN and Runx2 mRNA expression elevated in both groups after JBMMSCs osteogenic induction, but the expression in the type 2 diabetes group was lower than that in the control group (P<0.05), and calcium nodule forming ability and ALP staining area and density in the type 2 diabetes group were lower than those in the control group (P<0.05). After adipogenic induction, the expression level of adipogenesis-related genes and lipid droplet formation in the type 2 diabetes group reduced compared with the control group (P<0.05). The mRNA expression levels of Wnt4, Wnt5a and Wnt7b related to the Wnt signal pathway in the type 2 diabetes group were higher than those in the control group at 7 days after JBMMSCs osteogenesis induction, while the expression level of β-catenin was lower than that in the control group.

  Conclusion  Type 2 diabetes inhibits the proliferation, cloning, osteogenic and adipogenic differentiation of JBMMSCs, and the reduction of their osteogenic capacity may be related to the Wnt signaling pathway.