The protective effects of saxagliptin onβ-cell proliferation by inhibiting the degradation of SDF-1 in type 2 diabetes rats / 天津医药

ABSTRACT

Objective To investigate the mechanism of a dipeptidyl-peptidase-4 (DPP-4) inhibitor, saxagliptin, pro?moting the regeneration of islet beta cells in diabetic rats. Methods The male SD rats were randomly divided into three groups including control group (NC, n=10), diabetes group (DM, n=10) and diabetes treated with saxagliptin group (DM-S, n=10). DM-S group was treated with saxagliptin 1 mg/(kg·d) for twelve weeks. The pancreaticβcell function was analysed by hyperglycemic clamps. Immunohistochemistry with anti-PCNA was performed to observe the proliferation rate of pancreaticβcells. Immunofluorescence double staining with anti-insulin, anti-glucagon, anti-DPP-4 and anti-SDF-1 were performed to observe the expression of insulin, glucagon, DPP-4 and SDF-1 in pancreatic tissue. Western blot assay was performed to test the expression of Akt, p-Akt,β-catenin and free-β-catenin protein, and RT-PCR was performed to test the expressionlevels of c-myc and cyclinD1 mRNA in pancreatic tissue. Results Compared with NC group, there were significantly in?creased blood glucose, decreased islet function andβcell mass in DM group. Compared with DM rats, saxagliptin treatment significantly inhibited the expression of DPP-4, decreased the degradation of SDF-1, stimulated the proliferation ofβcells, and ultimately improved the islet function and histopathological changes of pancreas. Conclusion DPP-4 inhibitor saxa?gliptin can significantly improve islet function, which involved in the inhibition of the expression of DPP-4, the decreased degradation of SDF-1 and the stimulation of the proliferation ofβcells.