Cytoprotection by melatonin and growth hormone in early rat myocardial infarction as revealed by Feulgen DNA staining.
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.
Castagnino
Hugo E
HE
Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, 1121 Buenos Aires, Argentina.
Lago
Néstor
N
Centrella
José M
JM
Calligaris
Silvana D
SD
Fariña
Silvia
S
Sarchi
María I
MI
Cardinali
Daniel P
DP
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
D004396:Coloring Agents; C007722:Feulgen stain; D012394:Rosaniline Dyes; D013006:Growth Hormone; D004247:DNA; D008550:Melatonin