High-Fat Diet/Low-Dose Streptozotocin-Induced Type 2 Diabetes in Rats Impacts Osteogenesis and Wnt Signaling in Bone Marrow Stromal Cells

Bone regeneration disorders are a significant problem in patients with type 2 diabetes mellitus. Bone marrow stromal cells (BMSCs) are recognized as ideal seed cells for tissue engineering because they can stimulate osteogenesis during bone regeneration. Therefore, the aim of this study was to investigate the osteogenic potential of BMSCs derived from type 2 diabetic rats and the pathogenic characteristics of dysfunctional BMSCs that affect osteogenesis. BMSCs were isolated from normal and high-fat diet+streptozotocin-induced type 2 diabetic rats. Cell metabolic activity, alkaline phosphatase (ALP) activity, mineralization and osteogenic gene expression were reduced in the type 2 diabetic rat BMSCs. The expression levels of Wnt signaling genes, such as β-catenin, cyclin D1 and c-myc, were also significantly decreased in the type 2 diabetic rat BMSCs, but the expression of GSK3β remained unchanged. The derived BMSCs were cultured on calcium phosphate cement (CPC) scaffolds and placed subcutaneously into nude mice for eight weeks; they were detected at a low level in newly formed bone. The osteogenic potential of the type 2 diabetic rat BMSCs was not impaired by the culture environment, but it was impaired by inhibition of the Wnt signaling pathway, likely due to an insufficient accumulation of β-catenin rather than because of GSK3β stimulation. Using BMSCs derived from diabetic subjects could offer an alternative method of regenerating bone together with the use of supplementary growth factors to stimulate the Wnt signaling pathway.