Influence of Isradipine Treatment on Left Ventricular and Coronary Vascular Hypertrophy in Spontaneously Hypertensive Rats

Abstract

The purpose of this study was to ascertain if Isradipine treatment in spontaneously hypertensive rats (SHR) decreased hypertension-dependent left ventricular and coronary vascular hypertrophy. Twelve week male SHR were used in this study; one group of SHR was treated with Isradipine while the control group of SHR was left untreated. Age-matched normotensive Wistar-Kyoto rats (WKY) were utilized as a reference group. After 12 weeks of treatment rats were sacrificed. The hearts were removed and morphometric analysis was performed on the left ventricles. Isradipine treatment reduced systolic blood pressure in SHR. The heart/body weight ratio significantly increased in SHR and in Isradipine-treated SHR in comparison with WKY rats. Isradipine treatment decreased the left ventricular muscle fibre diameter and decreased the amount of focal necrosis in SHR. Different sized coronary arteries were also examined using a light microscope and an image analyzer. We found that the area occupied by the medial layer and the media-to-lumen ratio were significantly increased in comparison with WKY rats. In Isradipine-treated SHR the area of the medial layer and the media-to-lumen ratio in small and medium sized but not in large sized coronary arteries were significantly reduced in comparison with untreated SHR. The above results suggest that long term Isradipine treatment is not only able to reduce high blood pressure in SHR but is also able to counter the development of certain morphological changes often seen in the hypertensive heart and coronary arteries.