Dimethyl fumarate-mediated Nrf2/ARE pathway activation and glibenclamide-mediated NLRP3 inflammasome cascade inhibition alleviate type II diabetes-associated fatty liver in rats by mitigating oxidative stress and inflammation

The prevalence of nonalcoholic fatty liver disease (NAFLD) is much higher in patients with type II diabetes (T2D). Inflammasomes are multimolecular complexes reported to involve inflammatory conditions. The nuclear factor (erythroid-derived 2)-like factor 2/antioxidant responsive element (Nrf2/ARE) pathway is an important regulator of antioxidant status in cells. Antidiabetic drug glibenclamide (GLB) is reported as NACHT, leucine-rich repeat, and pyrin domain domains-containing protein 3 (NLRP3) inflammasome inhibitor, whereas anti-multiple sclerosis drug dimethyl fumarate (DMF) is reported as an Nrf2/ARE pathway activator. Both GLB and DMF possess anti-inflammatory and antioxidant properties, therefore, the hypothesis was made to look into the alone as well as the combination potential of GLB, DMF, and GLB + DMF, against NAFLD in diabetic rats. This study was aimed to investigate (1) the involvement of NLRP3 inflammasome and Nrf2/ARE signaling in diabetes-associated NAFLD (2) the effect of GLB, DMF, GLB + DMF, and metformin (MET) interventions on NLRP3 inflammasome and Nrf2/ARE signaling in diabetes-associated NAFLD. The rats were injected with streptozotocin (STZ) 35 mg/kg and fed a high-fat diet (HFD) for 17 consecutive weeks to induce diabetic NAFLD. The oral treatment of GLB 0.5 mg/kg/day, DMF 25 mg/kg/day, their combination and MET 200 mg/kg/day, were provided from the 6th to the 17th week. Treatment with GLB, DMF, GLB + DMF, and MET significantly alleviated HFD + STZ-induced plasma glucose, triglycerides, cholesterol, %HbA1c, hepatic steatosis, NLRP3, apoptosis-associated speck-like protein containing a caspase activation and recruitment domain, CARD, caspase-1, interleukin-1 beta (IL-1 beta), nuclear factor-kappa B (NF-kappa B), Nrf2, superoxide dismutase 1, catalase, IGF 1, heme oxygenase 1, receptor for the advanced glycation end product (RAGE), and collagen-1 in diabetic rats. Further, a mechanistic molecular study employing other specific NLRP3 inhibitors and Nrf2 activators will significantly contribute to the development of novel therapy for fatty liver diseases.