Saxagliptin alleviates erectile dysfunction through increasing stromal cell-derived factor-1 in diabetesmellitus.

Background: Diabetes mellitus-induced erectile dysfunction (DMED) is one of the complications of diabetes and has a poor response to phosphodiesterase type 5 inhibitor, the first-line treatment for ED. Saxagliptin (Sax), a dipeptidyl peptidase-4 inhibitor (DPP-4i), has been officially used in the treatment of type 2 diabetes. Stromal cell-derived factor-1 (SDF-1) is one of the important substrates of DPP-4, and has been proven to be beneficial for several DMcomplications. However, it is unknownwhether Sax contributes to the management of DMED. Objectives: To explore the effect and possible underlying mechanisms of Sax in the treatment of DMED. Methods: The model of DMwas established by intraperitoneal injection of streptozotocin. All rats were divided into three groups (n = 8 per group): control group, DMED group and DMED+Sax group. In cellular experiments, the corpus cavernosum smooth muscle cells (CCSMCs) were exposed to high glucose (HG), and treated with Sax and AMD3100 (SDF-1 receptor inhibitor). The penile tissue and CCSMCs were harvested for detection. Results: We found that erectile function was impaired in DMED rats compared with the control group, which was partially relieved by Sax. Decreased expression of DPP-4 and increased level of SDF-1 were also observed in DMED+Sax group, together with elevation of PI3K/AKT pathway and inhibition of endothelial dysfunction, oxidative stress and apoptosis in corpus cavernosum. Moreover, Sax could also regulate oxidative stress and apoptosis in CCSMCs underHGcondition, which was blocked in part by AMD3100. Conclusion: Sax could alleviate DMED through increasing SDF-1 and PI3K/AKT pathway, in company with moderation of endothelial dysfunction, oxidative stress and apoptosis. Our findings indicated that DPP-4 is may be beneficial to the management of DMED. [ABSTRACT FROM AUTHOR]