ABSTRACT
In this study we investigated the histological role of estrogen on Fatty Streak [FS]formation in some branches of coronary arteries [CA] in cholesterol-fed diabetic male rabbits. Seventeen rabbits were obtained from Pasteur Institute of Iran and diabetes was induced by intravenous injection of Alloxan [200 mg/kg]. After induction of diabetes, they were randomly divided into three groups: [i] control, [ii] low-dose estrogen treatment [1mg/animal] and [iii] high-dose estrogen treatment [5mg/animal]. Estrogen was injected i.m, weekly. Control group received normal saline injection. All groups were fed with cholesterol rich diet [1%] during the experiment. After six weeks, the animals were sacrificed. Hearts were isolated and four branches of CA [Right and Left CA; RCA and LCA, Anterior and Posterior interventricular arteries; AIVA and PIVA] were dissected and evaluated for the relative size of FS and the percentage of arterial lumen narrowing by FS using scale micrometer. The average grades of pathological evaluation for branches of coronary crteries showed that in animals receiving high dose estrogen, the FS formations in RCA, LCA, AIVA and P1 VA [0.33 +/- 0.21, 0.17 +/- 0.17, 0.0 +/- 0.0, 0.0 +/- 0.0, respectively] were significantly lesser than control group [1.40 +/- 0.24, 2.2 +/- 0.37, 0.80 +/- 0.2, 1.20 +/- 0.37, respectively]. We conclude that estrogen has a beneficial role in histological changes of coronary arteries, it can attenuate progression of FS formation administration diabetic rabbits