title: Beta blocker metoprolol protects against contractile dysfunction in rats after coronary microembolization by regulating expression of myocardial inflammatory cytokines.
abstract: OBJECTIVE
  To examine the effects of metoprolol on expression of myocardial inflammatory cytokines and myocardial function in rats following coronary microembolization (CME).
  
  
  METHODS
  Male rats were randomly assigned to receive either sham-operation (control group), CME plus saline (CME group), or CME plus metoprolol (metoprolol group). CME was induced by injecting 3000 polyethylene microspheres (42 μm) into the left ventricle during a 10-second occlusion of the ascending aorta. Metoprolol (2.5mg/kg) or saline was administered as three intravenous bolus injections after CME. At 3h, 6h, 12h, 24h and 4 weeks after CME, myocardial function was measured with echocardiography; and the mRNA and protein levels of tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10) and interleukin 1-β (IL-1β) were determined.
  
  
  RESULTS
  Induced CME led to markedly higher mRNA and protein levels of TNF-α, IL-1β and IL-10 at 3, 6, 12, and 24h, as well as reduced left ventricular function, compared to the control group. Metoprolol administration reduced TNF-α and IL-1β levels, but increased IL-10 levels at 3, 6, 12, and 24h compared to the CME group. Moreover, metoprolol treatment resulted in significantly improved left ventricular function at 12h, 24h and 4 weeks, but afforded no cardiac protection at 3h and 12h, compared to the CME group.
  
  
  CONCLUSIONS
  Higher levels of TNF-α and IL-1β in rats following CME are associated with the development of myocardial contractile dysfunction. Metoprolol-conferred protection against progressive contractile dysfunction following CME may be mediated by its anti-inflammation potential.
authors: Department of Cardiology, the First Affiliated Hospital of Guangxi Medical University, Nanning city, Guangxi province, China.
authors: Yongguang
authors: Y
authors: Lu
authors: Lang
authors: L
authors: Li
authors: Xianming
authors: X
authors: Zhao
authors: Weiqiang
authors: W
authors: Huang
authors: Weiming
authors: W
authors: Wen
mesh_terms: D058671:Adrenergic beta-1 Receptor Antagonists / Q000494:pharmacology*; D000818:Animals; D004195:Disease Models, Animal; D004452:Echocardiography; D004617:Embolism / Q000150:complications*; D016753:Interleukin-10 / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism; D008297:Male; D008790:Metoprolol / Q000494:pharmacology*; D008863:Microspheres; D009200:Myocardial Contraction / Q000187:drug effects*; D020959:Polyethylene; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D018487:Ventricular Dysfunction, Left / Q000188:drug therapy*
chemical_list: D058671:Adrenergic beta-1 Receptor Antagonists; D053583:Interleukin-1beta; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D020959:Polyethylene; D008790:Metoprolol