Aims Glycemic variability has been shown to be more harmful in the development of diabetic complication than sustained chronic hyperglycemia. In this present study, we tried to reveal the effects of glycemic variability on cardiac damage in diabetic mice and investigate whether sodium-glucose cotransporter 1 (SGLT1), an important cardiac glucose transporter, functions as an important mediator in the process. Materials and methods Type 2 diabetes mellitus (DM) mice were induced by a high-fat diet and intraperitoneal injection of streptozotocin (STZ), and then glycemic variability in type 2 diabetes mellitus (GVDM) was induced by alternately injecting insulin and glucose to DM mice. In order to determine the roles of SGLT1 in GVDM mice, SGLT1 inhibition was performed using shRNA against SGLT1. The blood glucose level, the cardiac function and myocardial injury were assessed. And the expressions of SGLT1 and the activations of NLRP3/caspase-1 pathway and NF-κB in left ventricular tissues were measured. Key findings The results showed that SGLT1 was highly expressed in heart of GVDM mice compared to control and DM groups, and knockdown of SGLT1 reduced glycemic variability in GVDM mice. Moreover, glycemic variability impaired cardiac function, aggravated cardiac injury and induced NLRP3/caspase-1-mediated inflammatory response and pyroptosis. And knockdown of SGLT1 significantly attenuated the cardiac damages that induced by glycemic variability. Significance The results indicated that glycemic variability could cause cardiac damage and induce inflammatory response and pyroptosis of cardiomyocytes in diabetic mice, which could be partially blocked by SGLT1 silence.
α-Mangostin is a natural xanthone derivative isolated from Camellia atrophy (CA), commonly known as Lichuan black tea (LBT). The present study investigated the ameliorating effect and mechanism of α-mangostin on alcoholic gastric ulcers (GU) in rats. In vivo , α-mangostin relieved pathological symptoms. Moreover, α-mangostin regulated the activation of the nuclear factor (erythroid-derived 2)-like 2 (Nrf2)/heme oxygenase 1 (HO-1) and nuclear factor κB (NF-κB)/NLR family pyrin domain containing 3 (NLRP3)/caspase-1 pathways. Reactive oxygen species (ROS), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) were significantly decreased and IL-10 were increased, the microtubule-associated protein light chain 3 (LC3)-II/LC3-I ratio was increased, p62 protein expression was decreased, and inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) protein expression was down-regulated. The relevant mechanisms were validated using GSE-1 and RAW264.7 cells in an in vitro model. Furthermore, α-mangostin increased Ligilactobacillus and Muribaculum abundance as well as propionic acid and butyric acid contents. Therefore, α-mangostin possesses antioxidant and anti-inflammatory properties, and remodels intestinal flora dysbiosis through mechanisms that may involve regulation of the Nrf2/HO-1 pathway and NF-κB/NLRP3/caspase-1 pathway. It also increases propionic acid and butyric acid contents. This study provides novel evidence regarding the use of α-mangostin for treating GU.