title: Histopathological evaluation of melatonin as a protective agent in heart injury induced by radiation in a rat model.
abstract: BACKGROUND
  Melatonin is a hormone which is known to be a powerful cardioprotective agent due to its free radical-scavenging properties. This study was carried out to evaluate whether melatonin administration prior to irradiation would have a protective effect on cardiac histopathological changes in an experimental rat model.
  
  
  METHODS
  Rats were divided into four groups. Single dose of 18 Gy radiation and sham radiation exposure were used in related groups. 50mg/kg dose of melatonin were injected intraperitonally 15 min prior to radiation exposure. Analyses and assessments were performed 6 months after radiation exposure.
  
  
  RESULTS
  Severe myocardial fibrosis was observed prominently in three regions: the apex, tips of papillary muscles and adjacent to the atrioventricular valves. Inflammation was found to be more in irradiated groups. Increased inflammation and fibrosis were in concordance. The number of mast cells was found to be decreased in irradiated groups. Myocyte necrosis and fibrosis were diminished with melatonin while vasculitis was prevented.
  
  
  CONCLUSIONS
  Elementary pathological lesions of radiation-induced heart disease (RIHD) are fibrosis, vascular damage, vasculitis and myocyte necrosis. Development of vasculitis was prevented by the use of melatonin. Fibrosis and necrosis were prominently decreased. Prevention of RIHD with the use of melatonin at the long term is encouraging according to the histopathological results.
authors.affiliation: Mersin University Medical Faculty, Department of Pathology, Mersin, Turkey. Electronic address: iclalgurses@gmail.com.
authors.forename: Iclal
authors.initials: I
authors.lastname: Gürses
authors.affiliation: Mersin University Medical Faculty, Department of Cardiovascular Surgery, Mersin, Turkey. Electronic address: mozeren@yahoo.com.
authors.forename: Murat
authors.initials: M
authors.lastname: Özeren
authors.affiliation: Acıbadem University Adana Hospital, Department of Radiation Oncology, Adana, Turkey. Electronic address: m_serin@hotmail.com.
authors.forename: Meltem
authors.initials: M
authors.lastname: Serin
authors.affiliation: İnönü University Medical Faculty, Department of Emergency Medicine, Malatya, Turkey. Electronic address: neslihan.yucel@inonu.edu.tr.
authors.forename: Neslihan
authors.initials: N
authors.lastname: Yücel
authors.affiliation: Sakarya University Medical Faculty, Department of Radiation Oncology, Sakarya, Turkey. Electronic address: hserkal@sakarya.edu.tr.
authors.forename: Haldun Şükrü
authors.initials: HŞ
authors.lastname: Erkal
mesh_terms: D000818:Animals; D009202:Cardiomyopathies / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*; D003324:Coronary Artery Disease / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*; D003331:Coronary Vessels / Q000187:drug effects* / Q000473:pathology / Q000528:radiation effects; D019610:Cytoprotection; D005355:Fibrosis; D008297:Male; D008407:Mast Cells / Q000187:drug effects / Q000473:pathology / Q000528:radiation effects; D008550:Melatonin / Q000494:pharmacology*; D009205:Myocarditis / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000473:pathology / Q000528:radiation effects; D009336:Necrosis; D011833:Radiation Injuries, Experimental / Q000473:pathology / Q000517:prevention & control*; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D017208:Rats, Wistar; D013997:Time Factors; D014657:Vasculitis / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*
chemical_list: D011837:Radiation-Protective Agents; D008550:Melatonin
keywords: Histopathology; Irradiation; Melatonin; Radiation-induced heart disease; Radioprotection