Late protective effect of pharmacological preconditioning with total flavones of rhododendra against myocardial ischemia-reperfusion injury.
The aim of the present study was to investigate the protective effect of total flavones of rhododendra (TFR) pharmacological preconditioning against myocardial ischemia-reperfusion (I/R) injury and its probable mechanisms in rats. Rat myocardial I/R injury was induced by ligating and untying the left anterior descending coronary artery. Male Sprague-Dawley rats were anesthetized and the chests were opened. All animals were subjected to 30 min of occlusion and 1 h of reperfusion. Twenty-four hours before the 30-minute occlusion, rats received 3 cycles of 5 min intravenous perfusion of TFR (10, 20, 40 mg/kg) or morphine hydrochloride (0.3 mg/kg) or normal saline interspersed with drug-free periods. Changes in the ST segment of ECG, the content of cardiac troponin I (cTnI), malondialdehyde (MDA), and nitric oxide (NO), and the activity of superoxide dismutase (SOD), lactate dehydrogenase (LDH), creatine phosphokinase (CK), and nitric oxide synthase (NOS) in serum were measured. Infarct size (IS), as a percentage of the area at risk (AAR), was determined by TTC staining. The expression of inducible nitric oxide synthase (iNOS) mRNA in rat myocardium was detected by RT-PCR and the expression of iNOS protein was detected by Western blot. Pretreatment with TFR (10, 20, 40 mg/kg) markedly inhibited I/R-induced ST segment elevation of ECG. TFR (20, 40 mg/kg) pretreatment decreased I/R-induced IS/AAR, markedly inhibited the increase of MDA content and the activity of CK and LDH, and also significantly inhibited the decline of NO content and the activity of NOS and SOD in serum. TFR (40 mg/kg) preconditioning significantly inhibited the increase of serum cTnI induced by I/R injury and increased the expression of iNOS both at mRNA and protein levels in rat myocardium. Our findings indicate that TFR preconditioning has a protective effect against myocardial I/R injury in rats. The cardioprotection involves the stimulation of NO release and the inhibition of lipid peroxidation.
Zhang
Jian-Hua
JH
Department of Pharmacology, Anhui Medical University, Hefei, Anhui 230032, China.
Chen
Zhi-Wu
ZW
Wu
Zheng
Z
D000818:Animals; D015153:Blotting, Western; D003402:Creatine Kinase / Q000097:blood; D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography / Q000187:drug effects; D047309:Flavones / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D007118:Immunoassay; D019157:Ischemic Preconditioning, Myocardial; D007770:L-Lactate Dehydrogenase / Q000097:blood; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D009203:Myocardial Infarction / Q000097:blood / Q000517:prevention & control; D015428:Myocardial Reperfusion Injury / Q000097:blood / Q000503:physiopathology / Q000517:prevention & control*; D009569:Nitric Oxide / Q000097:blood; D019001:Nitric Oxide Synthase / Q000097:blood; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism; D008517:Phytotherapy; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D029793:Rhododendron / Q000737:chemistry*; D013482:Superoxide Dismutase / Q000097:blood; D013997:Time Factors; D019210:Troponin I / Q000097:blood
D047309:Flavones; D012333:RNA, Messenger; D019210:Troponin I; D009569:Nitric Oxide; D008315:Malondialdehyde; D007770:L-Lactate Dehydrogenase; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D013482:Superoxide Dismutase; D003402:Creatine Kinase