SGLT2 Inhibition Attenuates Renal Interstitial Inflammation and Fibrosis in the Model of Unilateral Ureteral Obstruction, with No Interference on Hexokinase 1-Dependent Glycolytic Pathway

Background: Sodium-Glucose cotransport 2 inhibitors (SGLT-2i) exert nephroprotective effects, independent of glycemic control. Previous studies showed the role of the glycolytic pathway in the pathogenesis of renal inflammation and fibrosis in the model of unilateral ureteral obstruction (UUO). This study addressed the effects of Empagliflozin (Empa), an SGLT-2 inhibitor, on the renal inflammation and interstitial fibrosis of UUO in rats and attempted to test hexokinase1 (HK1) gene expression in the process of canonical glycolysis in this setting. Methods: Male Wistar rats were submitted to left UUO for 14 days. Four groups of animals were as follows: Group 1(G1): Sham; Group 2(G2): UUO; Group 3(G3): UUO+Empa; Group 4(G4): Sham+Empa. The animals were pretreated with Empa for 7 days and during 14 days of UUO in groups 3 and 4. On day 14, rats were sacrificed and the kidneys prepared for histology (HE and Picrosirius), immunohistochemistry for ED-1 (macrophages), SMA (myofibroblasts), TGF-β1 and SGLT-2. Real time PCR was performed for HK1 and IL-1β gene expression. Results are mean±SD or median[25-75%] and were significant when P<0.05. Results: Histological findings revealed less cellularity (HE) and lower Picrossirius (PS) staining in G3 (2.3[1.3-3.9], compared to G2 (7.7[5.7-12.2], %area, P<0.0001). In addition, the effect of SGLT-2i on ED-1, (SMA) and TGF-β1 expression were significantly attenuated in Empa treated UUO rats (G3), compared to UUO (G2), (0.32[0.1-0.6] versus 9.6[6.5-14.2], P<0.0001, 1.0±1.0 versus 3.6±2.8, P<0.0001, 3.1±2.4 versus 7.0±6.6, as % area, respectively. Interestingly, the expression of SGLT-2 was blunted in G2 and was partly recovered in the Empa group (G3), (G3: 0.4±0.3 versus G2: 1.5±0.5, x10-3 %area, P<0.01). PCR study revealed lower quantification (RQ) of HK1 mRNA in G2 group (0.7±0.3), and G3 group (0.6±0.2), both compared to G1 (1.0±0.3) and G4 (1.0±0.1), (NS). IL-1β gene expression was significantly lower in G3 (3.0±3.5) compared to G2 (11.8±4.1), with G1=1.0±0.2 and G4=0.7±0.2), (P<0.0001). Conclusion: Empagliflozin attenuated renal inflammation and interstitial fibrosis of UUO in rats, an effect related to IL-1β gene transcription, independently of glycolytic canonical HK1 gene activation. Funding: Government Support – Non-U.S.