ABSTRACT
OBJECTIVES: This study was conducted to explore whether microRNA-146a and its adapter proteins (TNF-α receptor-associated factor 6 (TRAF6) and interleukin-1 receptor-associated kinase 1 (IRAK1)) are affected by diabetes in the rat heart. METHODS: Twelve male Sprague-Dawley rats were randomized into control and diabetic groups (n = 6). Streptozotocin-nicotinamide experimental model was used to induce type 2 diabetes. The gene expression of MicroRNA-146a, nuclear factor-κB (NF-κB), IRAK1 and TRAF6, as well as NF-κB activity, IRAK1 and TRAF6 protein levels were measured. Moreover, NF-κB activity was measured in response to miR-146a mimic transfection (20 nmol) in human umbilical vein endothelial cells (HUVECs) under hyperglycemic condition (25 mM D-glucose for 24 h). RESULTS: The expression of MicroRNA-146a was increased in the heart tissue, 2 months after diabetes induction and in HUVECs. Also, the mRNA and protein levels of NF-κB, IRAK1 and TRAF6 were increased in the heart of diabetic rats. Moreover, transfection of miR-146a mimic prevented from a significant increase of NF-κB activity in hyperglycemic HUVECs. CONCLUSION: Presumably, a defect in the regulation of IRAK1 and TRAF6 can weaken miR-146a regulatory effect and provides a situation for sustained activation of NF-κB and its targets to promote cardiac cells toward abnormalities (Fig. 3, Ref. 28).
Subject(s)
Diabetes Mellitus, Experimental/metabolism , Interleukin-1 Receptor-Associated Kinases/metabolism , MicroRNAs/metabolism , Myocardium/metabolism , NF-kappa B/metabolism , TNF Receptor-Associated Factor 6/metabolism , Animals , Diabetes Mellitus, Type 2/metabolism , Gene Expression , Glucose , Human Umbilical Vein Endothelial Cells , Humans , Male , Rats , Rats, Sprague-DawleyABSTRACT
Ischemic brain injury is a leading cause of sever neurological and neurobehavioral deficits and death. The hippocampus plays vital roles in learning and memory processes and it is impaired by ischemic insults. Cerebral ischemia/reperfusion leads to Oxidative stress damage impairing the hippocampus. Here we tested whether ascorbic acid and adenosine receptor played a neuroprotective role in a mouse brain ischemia model induced by common carotid arteries occlusion. Adult male mice were randomly assigned into nine experimental groups. The animals were subjected to ischemia by the ligation of common carotid arteries for 15 min. Drugs were injected intrapritoneally once daily for 7 days. Behavioral tests performed at day 14 and then mice were killed at day 21 and their brains were fixed for microscopic studies and some samples were prepared for western blot analysis. Western blot analysis utilized to evaluate the expression of apoptosis-related proteinsin the hippocampus. Short-term memory was assessed by shuttle-box test. Our findings revealed that administration of vitamin C and N6-cyclopentyladenosine (CPA) significantly attenuated ischemia-induced brain injury. Vitamin C and CPA administration increased the expression of anti-apoptotic protein Bcl-2 and decreased the expression of pro-apoptotic protein Bax in the ischemic mice. Ischemia caused short-term memory loss that was improved by vitamin c and CPA treatment. Our results demonstrate that treatment with vitamin C and adenosine receptor agonist attenuated cerebral ischemia/reperfusion-induced brain injury as a potential neuroprotective agent.
Subject(s)
Antioxidants/pharmacology , Ascorbic Acid/pharmacology , CA1 Region, Hippocampal/pathology , Neuroprotective Agents , Receptors, Purinergic P1/drug effects , Reperfusion Injury/pathology , Reperfusion Injury/prevention & control , Adenosine/analogs & derivatives , Adenosine/pharmacology , Adenosine A1 Receptor Agonists/pharmacology , Adenosine A1 Receptor Antagonists/pharmacology , Animals , Avoidance Learning/drug effects , Behavior, Animal/drug effects , Blotting, Western , In Situ Nick-End Labeling , Male , Maze Learning/drug effects , Memory, Short-Term/drug effects , Mice , Proto-Oncogene Proteins c-bcl-2/metabolism , Xanthines/pharmacology , bcl-2-Associated X Protein/metabolismABSTRACT
INTRODUCTION: Stroke is one of the most important reasons of death. Hence, trials to prevent or lessen the complications originated by stroke are a goal of public health worldwide. The ischemia-reperfusion causes hypoxia, hypoglycemia and incomplete repel of metabolic waste products and leads to accumulation of free radicals triggering neuronal death. The A1 adenosine receptoras an endogenous ligand of adenosine is known to improve cell resistance to destructive agentsby preventing apoptosis. Vitamin C as a cellular antioxidant is also known as an effective factor to reduce damages initiated by free radicals. We studied the protective effects of A1 receptor agonist in combination with vitamin C against ischemia-reperfusion. METHODS: Ischemia was induced by common carotid artery occlusion in bulb-c mice (20-30 gr). Y-Maze was employed to scale the short-term memory and Nissl staining was used to count the cells in hippocampus. RESULTS: We found that concurrent treatment of A1 receptor agonist and vitamin C significantly reduced neuronal death in CA1. The Memory scores were also significantly improved (P < 0.05). DISCUSSION: Our data point to the therapeutic effects of CPA/vitamin C co-administration and highlight the beneficial role of A1 adenosine receptor signaling in the context of stroke.
