Estrogen alone or combined with medroxyprogesterone but not raloxifene reduce myocardial infarct size.
We investigated whether estrogen protects the ischemic myocardium in oophorectomized female rabbits fed with a cholesterol-enriched diet, whether the addition of a progestin compound attenuates the beneficial effect of estrogen and whether raloxifene also limits myocardial necrosis. We treated 32 female oophorectomized hypercholesterolemic rabbits with (a) placebo (N=8, group I), (b) conjugated estrogens alone (N=8, group II), (c) conjugated estrogens combined continuously with medroxyprogesterone acetate (N=8, group III) and (d) raloxifene (N=8, group IV) all for 4 weeks. All rabbits underwent 30 min of ischemia and 120 min of reperfusion. Both infarct size (0.38+/-0.08 and 0.45+/-0.05 in groups II and III, respectively, vs. 0.78+/-0.07 in group I, P<0.005) and infarct size/risk zone% (26.34+/-4.18 and 35.01+/-4.39 in groups II and III, respectively, vs. 52.18+/-7.84 in group I, P<0.05) were significantly smaller in the estrogen treatment groups compared to placebo. No significant difference was observed between groups II and III. There was no significant difference between groups I and IV for infarct size (0.78+/-0.07 vs. 0.69+/-0.08, respectively) or for infarct size/risk zone% (52.18+/-7.84 vs. 47.17+/-4.3). Short-term estrogen protects ischemic myocardium in hypercholesterolemic oophorectomized female rabbits; this effect is not attenuated by the addition of a progestin compound. Raloxifene, however, does not decrease infarct size compared to placebo.
Sbarouni
Eftihia
E
2nd Department of Cardiology, Onassis Cardiac Surgery Center, 356 Syngrou Avenue, 176 74 Athens, Greece. elbee@ath.forthnet.gr
Iliodromitis
Efstathios K
EK
Bofilis
Elias
E
Kyriakides
Zenon S
ZS
Kremastinos
Dimitrios Th
DT
D000818:Animals; D004359:Drug Therapy, Combination; D004965:Estrogen Antagonists / Q000627:therapeutic use*; D004967:Estrogens / Q000627:therapeutic use*; D005260:Female; D006937:Hypercholesterolemia / Q000150:complications; D008525:Medroxyprogesterone / Q000627:therapeutic use*; D009203:Myocardial Infarction / Q000188:drug therapy* / Q000209:etiology / Q000473:pathology; D009336:Necrosis; D010052:Ovariectomy; D045167:Progesterone Congeners / Q000494:pharmacology / Q000627:therapeutic use*; D011817:Rabbits; D020849:Raloxifene Hydrochloride / Q000627:therapeutic use*
D004965:Estrogen Antagonists; D004967:Estrogens; D045167:Progesterone Congeners; D020849:Raloxifene Hydrochloride; D008525:Medroxyprogesterone