Independent Effects of Exercise and Sodium–glucose Cotransporter 2 Inhibition on Markers of MAFLD in a Rat Model of Type 2 Diabetes

Type 2 diabetes mellitus (T2DM) and metabolic-associated fatty liver disease (MAFLD) are interrelated conditions characterized by dysregulated metabolism. Excess hepatic lipid accumulation and mitochondrial dysfunction lead to lipotoxicity, oxidative stress, and inflammation, and can contribute to MAFLD progression. Since exercise and sodium–glucose cotransporter 2 inhibitors (SGLT2i), a class of T2DM medication, improve glucose regulation and reduce substrate overload in T2DM, they may also benefit MAFLD by reducing hepatic lipid accumulation and oxidative stress, and ultimately helping to limit disease progression. Sirtuins play important roles in regulating hepatic fatty-acid metabolism and mitochondrial function, highlighting their potential involvement in modulating MAFLD progression. Objective: To assess the effects of SGLT2i, EX, and their combination on known contributors to the development and progression of MAFLD in a rat model of T2DM. Hypothesis: Compared with untreated sedentary animals, SGLT2i, EX, and their combination would have lower hepatic lipid-metabolism (uptake, synthesis, and storage); inflammatory, oxidative/antioxidant, and profibrotic markers; and would alter Sirtuin 1/3 expression. Methods: Hyperglycemia was induced in male Sprague-Dawley rats using low-dose streptozotocin (30 mg/kg) in combination with a high-fat diet (45% kcal from fat). Animals were allocated to four groups: vehicle sedentary (VEH SED), vehicle exercise (VEH EX), SGLT2i sedentary (SGLT2i SED), or SGLT2i exercise (SGLT2i EX), and treated for 12 weeks. SGLT2i groups received canagliflozin (3 mg/kg/day prepared in 0.5% methylcellulose), whereas VEH groups received 0.5% methylcellulose alone. Exercise groups completed treadmill training (60 min/day, 5 days/week, 10% incline, ~50–55% Vmax). Results: Neither EX nor SGLT2i affected CPT1a gene expression, a marker of mitochondrial fatty-acid uptake. SCD1 gene expression, a marker of de novo lipogenesis, was 42% lower in SGLT2i groups compared with VEH (p = 0.07). PPARγ protein expression, a marker of lipid-storage, did not differ between groups. SPTLC1 protein, a sphingolipid-biosynthesis marker, was higher with SGLT2i (p = 0.003). SGLT2i groups also had higher SIRT3 protein expression (p = 0.04), while SIRT1 was not different between treatments. Pro-inflammatory gene expression of IL-1β (36% lower; p = 0.03) and TNF-α (20% lower; p = 0.12) were reduced with EX, while MCP-1 and the anti-inflammatory marker IL-10 showed no differences between groups. Neither intervention affected the lipid peroxidation marker HNEJ but Nrf2 (p = 0.002), a transcriptional regulator of antioxidant defense, and its cytosolic inhibitor Keap1 (p = 0.02) had lower gene expressions with SGLT2i. SGLT2i also had lower expression of downstream antioxidant-related markers NQO1 (p = 0.005) and SOD1 (p = 0.03), while HO-1, GPX1, and GPX4 were not different with either treatment. SGLT2i groups also had lower gene expression of pro-fibrotic genes α-SMA (p = 0.022) and COL1A1 (p = 0.03) and had ~35% lower COL1A1 protein expression (p = 0.10). Conclusion: EX and SGLT2i had independent and distinct effects on markers related to MAFLD development and progression. EX had lower pro-inflammatory gene expression, whereas SGLT2i had lower indices of lipid-metabolism markers related to steatosis development, fibrosis, and antioxidants, indicative of lower oxidative stress. Together, these findings highlight SGLT2i as a promising strategy to mitigate MAFLD. Grant funding: This work was supported by Pfizer Inc and NIH NIDDK DK064584 This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.