Bin Zhou

The reactive oxygen species‐ (ROS‐) induced nod‐like receptor protein‐3 (NLRP3) inflammasome triggers sterile inflammatory responses and pyroptosis, which is a proinflammatory form of programmed cell death initiated by the activation of inflammatory caspases. NLRP3 inflammasome activation plays an important role in myocardial ischemia/reperfusion (MI/R) injury. Our present study investigated whether diabetes aggravated MI/R injury through NLRP3 inflammasome‐mediated pyroptosis. Type 1 diabetic rat model was established by intraperitoneal injection of streptozotocin (60 mg/kg). MI/R was induced by ligating the left anterior descending artery (LAD) for 30 minutes followed by 2 h reperfusion. H9C2 cardiomyocytes were exposed to high glucose (HG, 30 mM) conditions and hypoxia/reoxygenation (H/R) stimulation. The myocardial infarct size, CK‐MB, and LDH release in the diabetic rats subjected to MI/R were significantly higher than those in the nondiabetic rats, accompanied with increased NLRP3 inflammasome activation and increased pyroptosis. Inhibition of inflammasome activation with BAY11‐7082 significantly decreased the MI/R injury. In vitro studies showed similar effects, as BAY11‐7082 or the ROS scavenger N‐acetylcysteine, attenuated HG and H/R‐induced H9C2 cell injury. In conclusion, hyperglycaemia‐induced NLRP3 inflammasome activation may be a ROS‐dependent process in pyroptotic cell death, and NLRP3 inflammasome‐induced pyroptosis aggravates MI/R injury in diabetic rats.

Patients with diabetes are more vulnerable to myocardial ischemia/reperfusion (MI/R) injury, which is associated with excessive reactive oxygen species (ROS) generation and decreased antioxidant defense. Histone deacetylase 6 (HDAC6), a regulator of the antioxidant protein peroxiredoxin 1 (Prdx1), is associated with several pathological conditions in the cardiovascular system. This study investigated whether tubastatin A (TubA), a highly selective HDAC6 inhibitor, could confer a protective effect by modulating Prdx1 acetylation in a rat model of MI/R and an in vitro model of hypoxia/reoxygenation (H/R). Here, we found that diabetic hearts with excessive HDAC6 activity and decreased acetylated‐Prdx1 levels were more vulnerable to MI/R injury. TubA treatment robustly improved cardiac function, reduced cardiac infarction, attenuated ROS generation, and increased acetylated‐Prdx1 levels in diabetic MI/R rats. These results were further confirmed by an in vitro study using H9c2 cells. Furthermore, a study using Prdx1 acetyl‐silencing mutants (K197R) showed that TubA only slightly attenuated H/R‐induced cell death and ROS generation in K197R‐transfected H9c2 cells exposed to high glucose (HG), but these differences were not statistically significant. Taken together, these findings suggest that HDAC6 inhibition reduces ROS generation and confers a protective effect against MI/R or H/R injury by modulating Prdx1 acetylation at K197.

, i.g., once a day) was administered to DN rats for 8 weeks. The organ coefficient of kidneys was calculated. Levels of UP, BUN, Cr, FBG, TC and TG in serum were measured. Activities of SOD, CAT and GPx and the content of MDA in renal tissues were assayed. Pathological changes in renal tissues were observed by HE staining, PAS staining, PASM staining, Masson staining and transmission electron microscopy. p-NF-κB p65, TNF-α, TGF-β1, collagen IV, nephrin and podocin protein expressed in renal tissues were determined by immunohistochemistry and western blotting. Results showed that FA significantly improved the kidney organ coefficient, decreased the UP, BUN, Cr, FBG, TC and TG levels in serum, increased SOD, CAT and GPx activities, reduced MDA content in renal tissues and alleviated pathological injury of the renal tissues. What's more, long-term treatment with FA considerably down-regulated the expressions of p-NF-κB p65, TNF-α, TGF-β1 and collagen IV proteins, and up-regulated the expressions of nephrin and podocin proteins in renal tissues. FA could be a renoprotective agent by attenuating oxidative stress, inflammation, and fibrosis, as well as improving podocyte injury in STZ-induced DN rats.

PURPOSE: To investigate whether GDF11 ameliorates myocardial ischemia reperfusion (MIR) injury in diabetic rats and explore the underlying mechanisms. METHODS: Diabetic and non-diabetic rats subjected to MIR (30 min of coronary artery occlusion followed by 120 min of reperfusion) with/without GDF11 pretreatment. Cardiac function, myocardial infarct size, creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH), superoxide dismutase (SOD) 15-F2tisoprostane, autophagosome, LC3II/I ratio and Belcin-1 level were determined to reflect myocardial injury, oxidative stress and autophagy, respectively. In in vitro study, H9c2 cells cultured in high glucose (HG, 30mM) suffered hypoxia reoxygenation (HR) with/without GDF11, hydrogen peroxide (H2O2) and autophagy inhibitor 3-methyladenine (3-MA) treatment, cell injury; oxidative stress and autophagy were assessed. RESULTS: Pretreatment with GDF11 significantly improved cardiac morphology and function in diabetes, concomitant with decreased arrhythmia severity, infarct size, CK-MB, LDH and 15-F2tisoprostane release, increased SOD activity and autophagy level. In addition, GDF11 notably reduced HR injury in H9c2 cells with HG exposure, accompanied by oxidative stress reduction and autophagy up-regulation. However, those effects were completely reversed by H2O2 and 3-MA. CONCLUSION: GDF11 can provide protection against MIR injury in diabetic rats, and is implicated in antioxidant stress and autophagy up-regulation.