Background: The objective of this study was to assess the effect of intrahepatic injection of bone-derived green fluorescent protein (GFP)-transgenic murine mesenchymal stem cells (GFP-mMSCs) containing the human insulin(ins) gene in streptozotocin-induced diabetic mice.
Methods: GFP-mMSCs were isolated from the bone marrow of GFP transgenic mice, expanded, and transfected with a recombinant retrovirus MSCV carrying the human insulin gene. C57BL/6J mice were made diabetic by an intraperitoneal administration of 160 mg/kg streptozotocin (STZ), followed by intrahepatic injection of transfected GFP-mMSCs. The variations in body weight and the blood glucose and serum insulin levels were determined after cell transplantation. GFP-mMSCs survival and human insulin expression in liver tissues were examined by fluorescent microscopy and immunohistochemistry.
Results: The body weight in diabetic mice that received GFP-mMSCs harboring the human insulin gene was increased by 6% within 6 weeks after treatment, and the average blood glucose levels in these animals were 10.40 +/- 2.80 mmol/l (day 7) and 6.50 +/- 0.89 mmol/l (day 42), respectively, while the average values of blood glucose in diabetic animals without treatment were 26.80 +/- 2.49 mmol/l (day 7) and 25.40 +/- 4.10 mmol/l (day 42), showing a significant difference (p < 0.05). Moreover, secretion of human insulin of GFP-mMSCs in serum and animal liver was detected by radioimmunoassay (RIA) and immunohistochemistry (IHC).
Conclusions: Experimental diabetes could be relieved effectively for up to 6 weeks by intrahepatic transplantation of murine mesenchymal stem cells expressing human insulin. This study implies a novel approach of gene therapy for type I diabetes.