485-P: Proteomic Analysis Reveals Different Therapeutic Mechanisms for Diabetic Neuropathy between DPP-4 Inhibitor and SGLT2 Inhibitor

Aim: Diabetic neuropathy (DN) is the most prevalent complication with microangiopathy in diabetes. Although, DN would decrease quality of life, currently there is no radical treatment for DN. DPP-4 inhibitor (DP4i) and SGLT-2 inhibitor (SG2i) have been experimentally shown to possibly ameliorate DN. However, the difference in the mechanism between two agents has not been clarified so far. In this study, we performed proteomic analysis of the sciatic nerve (SN) and dorsal root ganglion (DRG) of Goto-Kakizaki rats (GK), a model of lean type 2 diabetes, treated with DP4i and/or SG2i.

Methods: Male GK and control Wister rats (W) were used. Since 5 weeks of age, GK rats were treated with 10mg/day DP4i (Te), 10mg/ day SG2i (Ca), and DP4i + SG2i (CaTe) until 29 weeks of age. Thermal perception was evaluated by tail flick test. At the end of experiment, SN, DRG, and skin tissue were dissected. Proteomic analysis was performed with SN and DRG tissues by mass spectrometry. In the skin, fluorescent immunostaining with anti-PGP 9.5 antibody was performed for the assessment of intraepidermal nerve density (IENFD).

Results: Tail flick test and IENFD were significantly decreased in GK compared to W (p<0.05), and significantly improved in Te, Ca, and CaTe (p<0.05, p<0.05 and p<0.01 vs GK, respectively). Proteomic analysis for SN showed only two pathways changed in Te, whereas seven and six pathways changed in the Ca and CaTe, respectively. Conversely, in the DRG, only two pathways changed in Ca, whereas the five and seven pathways changed in Te and CaTe, respectively.

Conclusion: Our results suggest that the DP4i and SG2i act on the different sites of peripheral nervous system with different mechanism. Combining these two agents possibly have complementary effects on DPN treatment.