Ovariektomize sıçanlarda bitkisel östrojenin iskemi-reperfüzyon aritmileri üzerine etkileri

More than 50% of sudden death in human occurring due to heart attack is caused by occlusion of coronary arteries. Ventricular arrhythmias that occurs due to the myocardial ischemia is the main reason of the sudden death. In most of the experimental researches, studies focus on these lethal arrhythmias and many chemical agents have been researched for the prevention of these arrhythmias. According to the previous researches, arrhythmia generation has been observed in females less than males. This difference has been based on gender differences which results from endogenous estrogen. There are many experimental studies that show protective effects of estrogen on ischemia and reperfusion induced arrhythmias. In recent years, plant derived substances that have a similar structure and function with estrogen have been used to prevent menopausal symptom in human being. Phytoestrogens are one of the examples of these substances. They are soy-derived substances which have a similar molecular shape with the endogenous estrogen. Genistein is the most known type of phytoestrogen and it has been used in the many experimental and clinical studies. Due to its similarity with estrogen, it was aimed to be researched whether it has a protective effect on ischemia and reperfusion induced arrhythmias in this study. Spraque-Dawley female rats weighing 225 - 290 g and in 6 - 7 months old were used. Myocardial ischemia were made by ligation of left coronary artery and reperfusion were made by releasing of this artery. Ovariectomy were made in two groups (ovx group). Genistein were given intraperitoneally in a dose of 100 µg / kg for 4 weeks in all groups except their control. Electrocardiogram (ECG) and arterial blood pressure were recorded during ischemia and reperfusion. It was found that plasma estradiol level significantly decreased in ovx group than the other group (p < 0,05). In genistein-treated group, no significant changes was observed in plasma estradiol level. There were no significant effect of genistein found on the total duration of arrhythmia and the incidence of ventricular tachycardia, ventricular premature contraction or ventricular fibrillation and arrhythmia score in unovariectomized and ovariectomized rats during 6 minutes of reperfusion. The effect of ovariectomy and genistein on the ischemia reperfusion induced arrhythmia was found similar as like previous studies. The nonsignificant different effect of genistein in the unovariectomised rats and ovariectomized rats was thought to be depend on the changes of its affinity to the estrogen receptor or the changes in the number of estrogen receptor after ovariectomy. More research is required to clarify the relation of genistein effect with the number of estrogen receptor and its affinity to the estrogen receptor.