title: Cytoprotection by melatonin and growth hormone in early rat myocardial infarction as revealed by Feulgen DNA staining.
abstract: OBJECTIVE
  To examine the cytoprotective effect of melatonin or recombinant human growth hormone (hGH) on the early phase of a running myocardial infarction in rats by using the Feulgen staining.
  
  
  METHODS
  Rats were subjected to surgical ligature of the left coronary artery or its sham-operation and were studied 1.5 3 h later. Melatonin was administered in the drinking water (100 microg/ml water) for 7 days before surgery. Recombinant hGH (2 IU/kg) was given ip at the time of surgery. Feulgen-stained histological cardiac sections were examined by light microscopy and image analysis.
  
  
  RESULTS
  Infarcted rats receiving vehicle exhibited large, diffuse cardiac lesions with a marked positivity for Feulgen reaction. About 18 20% of the total area recorded became injured 1.5 or 3 h after infarction, respectively. Infarcted rats treated with melatonin or hGH, or the combination of both, and killed 3 h after surgery, showed cardiac sections with scattered lesions and only a few isolated injured muscle fibers. A similar effectiveness of melatonin and hGH, alone or in combination, to decrease injured area by 86 87% and the number of cardiac lesions by 75 80% was observed.
  
  
  CONCLUSIONS
  A significant cytoprotective effect of melatonin or hGH is demonstrable in an early phase of myocardial infarction in rats.
authors.affiliation: Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, 1121 Buenos Aires, Argentina.
authors.forename: Hugo E
authors.initials: HE
authors.lastname: Castagnino
authors.forename: Néstor
authors.initials: N
authors.lastname: Lago
authors.forename: José M
authors.initials: JM
authors.lastname: Centrella
authors.forename: Silvana D
authors.initials: SD
authors.lastname: Calligaris
authors.forename: Silvia
authors.initials: S
authors.lastname: Fariña
authors.forename: María I
authors.initials: MI
authors.lastname: Sarchi
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Cardinali
mesh_terms: D000818:Animals; D004396:Coloring Agents; D019610:Cytoprotection / Q000187:drug effects*; D004247:DNA / Q000032:analysis; D004195:Disease Models, Animal; D004353:Drug Evaluation, Preclinical; D004359:Drug Therapy, Combination; D013006:Growth Hormone / Q000627:therapeutic use*; D006321:Heart / Q000187:drug effects*; D008297:Male; D008550:Melatonin / Q000627:therapeutic use*; D009203:Myocardial Infarction / Q000473:pathology / Q000517:prevention & control*; D009206:Myocardium / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D012394:Rosaniline Dyes; D016896:Treatment Outcome
chemical_list: D004396:Coloring Agents; C007722:Feulgen stain; D012394:Rosaniline Dyes; D013006:Growth Hormone; D004247:DNA; D008550:Melatonin