title: Low-level laser irradiation alters cardiac cytokine expression following acute myocardial infarction: a potential mechanism for laser therapy.
abstract: OBJECTIVE
  Low-level laser irradiation (LLLI) has the potential of exerting cardioprotective effect following myocardial infarction (MI). The authors hypothesized that LLLI could influence the expression of cardiac cytokines and contribute to the reversal of ventricular remodeling.
  
  
  BACKGROUND
  LLLI regulates the expression of cytokines after tissue damage. However, little is known concerning the alteration of the cardiac cytokine expression profile after LLLI.
  
  
  METHODS
  MI was created by coronary ligation. The surviving rats were divided randomly into laser and control groups. 33 rats were exposed to a diode laser (635  nm, 5  mW, CW, laser, beam spot size 0.8  cm(2), 6  mW/cm(2), 150  sec, 0.8  J, 1J/cm(2)) as laser group. Another 33 rats received only coronary ligation and served as control group. 28 rats received a thoracotomy without coronary ligation (sham group). One day after laser irradiation, 5 rats from each group were sacrificed and the heart tissues were analyzed by cytokine antibody arrays. Enzyme-linked immunosorbent assay (ELISA) was performed to confirm its reliability. Two weeks after MI, cardiac function and structure were evaluated by echocardiography and histological study.
  
  
  RESULTS
  Cytokine antibody array indicated 4 cytokines were significantly changed after laser therapy. ELISA confirmed that granulocyte-macrophage colony stimulating factor and fractalkine were the cytokines involved in the response to therapeutic laser irradiation. However, there was no difference in cytokine release between various groups at 2 weeks after MI. Although LLLI did not improve the damaged heart function, it did reduce the infarct area expansion.
  
  
  CONCLUSIONS
  The antibody-based protein array technology was applied for screening the cytokine expression profile following MI, with or without laser irradiation. The expression of multiple cytokines was regulated in the acute phase after LLLI. Our results revealed a potential novel mechanism for applying laser therapy to the treatment of heart disease.
authors.affiliation: Department of Surgery, Cardiovascular Institute and Fu Wai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Zhikai
authors.initials: Z
authors.lastname: Yang
authors.forename: Yihe
authors.initials: Y
authors.lastname: Wu
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.forename: Peifeng
authors.initials: P
authors.lastname: Jin
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Hou
authors.forename: Yingjie
authors.initials: Y
authors.lastname: Wei
authors.forename: Shengshou
authors.initials: S
authors.lastname: Hu
mesh_terms: D000818:Animals; D016207:Cytokines / Q000378:metabolism*; D004452:Echocardiography; D005260:Female; D066298:In Vitro Techniques; D028022:Low-Level Light Therapy; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology / Q000532:radiotherapy; D009206:Myocardium / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020257:Ventricular Remodeling / Q000528:radiation effects
chemical_list: D016207:Cytokines