title: N-acetylcysteine attenuates myocardial dysfunction and postischemic injury by restoring caveolin-3/eNOS signaling in diabetic rats.
abstract: Patients with diabetes are prone to develop cardiac hypertrophy and more susceptible to myocardial ischemia-reperfusion (I/R) injury, which are concomitant with hyperglycemia-induced oxidative stress and impaired endothelial nitric oxide (NO) synthase (eNOS)/NO signaling. Caveolae are critical in the transduction of eNOS/NO signaling in cardiovascular system. Caveolin (Cav)-3, the cardiomyocytes-specific caveolae structural protein, is decreased in the diabetic heart in which production of reactive oxygen species are increased. We hypothesized that treatment with antioxidant N-acetylcysteine (NAC) could enhance cardiac Cav-3 expression and attenuate caveolae dysfunction and the accompanying eNOS/NO signaling abnormalities in diabetes.
  
  
  
  Control or streptozotocin-induced diabetic rats were either untreated or treated with NAC (1.5 g/kg/day, NAC) by oral gavage for 4 weeks. Rats in subgroup were randomly assigned to receive 30 min of left anterior descending artery ligation followed by 2 h of reperfusion. Isolated rat cardiomyocytes or H9C2 cells were exposed to low glucose (LG, 5.5 mmol/L) or high glucose (HG, 25 mmol/L) for 36 h before being subjected to 4 h of hypoxia followed by 4 h of reoxygenation (H/R).
  
  
  
  NAC treatment ameliorated myocardial dysfunction and cardiac hypertrophy, and attenuated myocardial I/R injury and post-ischemic cardiac dysfunction in diabetic rats. NAC attenuated the reductions of NO, Cav-3 and phosphorylated eNOS and mitigated the augmentation of O2-, nitrotyrosine and 15-F2t-isoprostane in diabetic myocardium. Immunofluorescence analysis demonstrated the colocalization of Cav-3 and eNOS in isolated cardiomyocytes. Immunoprecipitation analysis revealed that diabetic conditions decreased the association of Cav-3 and eNOS in isolated cardiomyocytes, which was enhanced by treatment with NAC. Disruption of caveolae by methyl-β-cyclodextrin or Cav-3 siRNA transfection reduced eNOS phosphorylation. NAC treatment attenuated the reductions of Cav-3 expression and eNOS phosphorylation in HG-treated cardiomyocytes or H9C2 cells. NAC treatment attenuated HG and H/R induced cell injury, which was abolished during concomitant treatment with Cav-3 siRNA or eNOS siRNA.
  
  
  
  Hyperglycemia-induced inhibition of eNOS activity might be consequences of caveolae dysfunction and reduced Cav-3 expression. Antioxidant NAC attenuated myocardial dysfunction and myocardial I/R injury by improving Cav-3/eNOS signaling.
authors.affiliation: Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China.
authors.forename: Wating
authors.initials: W
authors.lastname: Su
authors.affiliation: Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China.
authors.forename: Qiongxia
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China.
authors.forename: Jinjin
authors.initials: J
authors.lastname: Xu
authors.affiliation: Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China.
authors.forename: Liying
authors.initials: L
authors.lastname: Zhan
authors.affiliation: Department of Anesthesiology, The Second Affiliated Hospital & Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Qiqi
authors.initials: Q
authors.lastname: Zhu
authors.affiliation: Department of Anesthesiology, The Second Affiliated Hospital & Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Qingquan
authors.initials: Q
authors.lastname: Lian
authors.affiliation: Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China.
authors.forename: Huimin
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China.
authors.forename: Zhong-Yuan
authors.initials: ZY
authors.lastname: Xia
authors.affiliation: Department of Anesthesiology, The Second Affiliated Hospital & Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China. zyxia@hku.hk.|Department of Anesthesiology, The University of Hong Kong, Hong Kong SAR, China. zyxia@hku.hk.
authors.forename: Zhengyuan
authors.identifier: 0000-0002-7002-5524
authors.initials: Z
authors.lastname: Xia
authors.affiliation: Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China. leishaoqing@163.com.
authors.forename: Shaoqing
authors.initials: S
authors.lastname: Lei
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology*; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D006332:Cardiomegaly / Q000139:chemically induced / Q000201:enzymology / Q000503:physiopathology / Q000517:prevention & control*; D021941:Caveolae / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D051244:Caveolin 3 / Q000235:genetics / Q000378:metabolism*; D015687:Cell Hypoxia; D002460:Cell Line; D019610:Cytoprotection; D003921:Diabetes Mellitus, Experimental / Q000139:chemically induced / Q000188:drug therapy*; D058065:Diabetic Cardiomyopathies / Q000139:chemically induced / Q000201:enzymology / Q000503:physiopathology / Q000517:prevention & control*; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D015428:Myocardial Reperfusion Injury / Q000139:chemically induced / Q000201:enzymology / Q000503:physiopathology / Q000517:prevention & control*; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D009569:Nitric Oxide / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects; D010766:Phosphorylation; D034622:RNA Interference; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects*; D013311:Streptozocin; D014162:Transfection; D016277:Ventricular Function, Left / Q000187:drug effects
chemical_list: D000975:Antioxidants; C495549:Cav3 protein, rat; D051244:Caveolin 3; D009569:Nitric Oxide; D013311:Streptozocin; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat; D000111:Acetylcysteine
keywords: Caveolin-3; Diabetes; Diabetic cardiomyopathy; Myocardial ischemia–reperfusion injury; N-acetylcysteine