Ginkgo biloba L. extract enhances the effectiveness of syngeneic bone marrow mesenchymal stem cells in lowering blood glucose levels and reversing oxidative stress

Bone marrow mesenchymal stem cells (BMSCs) are potential therapy for diabetes. Owing to the oxidative stress caused by hyperglycemia, these transplanted BMSCs are with high rate of apoptotic death after transplantation. Ginkgo biloba L. extract (EGB) is a potent antioxidant which can remove free radicals. The study was to investigate whether EGB can protect BMSCs from oxidative stress in vitro and enhance the efficacy of BMSCs in lowering blood glucose levels after transplantation. BMSCs were cultured with H₂O₂, EGB, or H₂O₂ and EGB. Cell viability, malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and cell death rates were determined. Diabetes was induced by single injection of streptozotocin (STZ) in male Wistar rats. Diabetic rats received EGB, BMSCs, or EGB/BMSCs. The serum levels of glucose, insulin, interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), MDA, SOD, and GSH-Px were determined. PKCα expression and NF-κB activation in kidney were determined. The MDA levels and cell death rates in BMSCs cultured with H₂O₂ and EGB were significantly lower; cell viability, SOD, and GSH-Px activities were significantly higher compared with those with H₂O₂ alone. Compared with diabetic rats receiving BMSCs, diabetic rats receiving EGB before BMSCs transplantation showed (1) significantly lower levels of blood glucose, serum MDA, IL-6, and TNF-α, and higher levels of insulin, SOD, and GSH-Px activities; (2) significantly lower PKCα expression and NF-κB activation in the kidney. EGB administration before BMSC transplantation can enhance the effectiveness of BMSCs in lowering blood glucose levels and reversing oxidative stress in diabetic rats.