Ghrelin protects myocardium from isoproterenol-induced injury in rats.
OBJECTIVE
To investigate the cardiac protective effects of ghrelin in rat with myocardial injury induced by isoproterenol (ISO).


METHODS
Rats were subcutaneously injected ISO 40 mg/kg/d with or without ghrelin 1 or 10 nmol/kg/d for 2 d. Hemodynamic parameters including mean arterial blood pressure and left ventricular pressure were measured at 12 h after the last injection with ISO and/or ghrelin. Plasma lactate dehydrogenase (LDH) activity, plasma and myocardial contents of malondialdehyde (MDA), and conjugated diene were measured. Plasma ghrelin and endothelin-1 levels were assayed using radioimmunoassay methods. Endothelin-1 and ghrelin mRNA were determined using RT-PCR.


RESULTS
About 45 % (5/11) of rats after treatment with ISO alone died during experimental periods. However, no rats died after administration with ghrelin 10 nmol/kg/d (0/11, P<0.05). Ghrelin also obviously ameliorated the hemodynamic disturbance in rats induced by ISO. The plasma LDH activity, contents of myocardial and plasma MDA, and conjugated diene level in plasma in ISO+G10 nmol/kg/d group were decreased by 28 %, 34 %, 73 %, and 38 % compared with those of ISO group (all P<0.01) respectively. ISO-induced endothelin-1 mRNA over-expression was inhibited and endothelin-1 level in plasma were inhibited by ghrelin 1 and 10 nmol/kg/d. The ghrelin levels in plasma and ghrelin mRNA in myocardium were increased in the rats after injection of ISO. The plasma ghrelin level was further increased after ghrelin administration.


CONCLUSIONS
Ghrelin has a protective effect against ISO-induced myocardial injury.
Chang
Lin
L
Institute of Cardiovascular Disease Research, the First Hospital Beijing 100034, China.
Zhao
Jing
J
Li
Gui-Zhong
GZ
Geng
Bin
B
Pan
Chun-Shui
CS
Qi
Yong-Fen
YF
Tang
Chao-Shu
CS
D000818:Animals; D002316:Cardiotonic Agents / Q000494:pharmacology*; D019332:Endothelin-1 / Q000096:biosynthesis* / Q000097:blood / Q000235:genetics; D054439:Ghrelin; D007545:Isoproterenol; D007770:L-Lactate Dehydrogenase / Q000097:blood; D008297:Male; D008315:Malondialdehyde / Q000097:blood / Q000378:metabolism; D017202:Myocardial Ischemia / Q000139:chemically induced / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism; D036361:Peptide Hormones / Q000096:biosynthesis / Q000235:genetics / Q000494:pharmacology*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley
D002316:Cardiotonic Agents; D019332:Endothelin-1; D054439:Ghrelin; D036361:Peptide Hormones; D012333:RNA, Messenger; D008315:Malondialdehyde; D007770:L-Lactate Dehydrogenase; D007545:Isoproterenol