Abstract

In the present study, we investigated the possible antihypertensive effect of Thymus vulgaris (T. vulgaris) and its possible protective role against hypertension-induced aorta damage in hypertensive rats. Hypertension was induced by ligation of left renal artery, andT. vulgaris aqueous extract was administered (100 mg/kg/day, orally) for 8 consecutive weeks. Systolic blood pressure, body weight, and the serum concentrations of creatinine and cholesterol were measured at the beginning and at the end of the study. Thoracic aorta was isolated at the end of the study for both light and electron microscopic examinations. The antihypertensive effect of T. vulgaris was clearly observed here, as well its significant reducing effect on hypertension-induced increases in serum levels of creatinine and cholesterol. The light microscopic findings indicated that the surface endothelium of thoracic aorta of hypertensive-untreated rats was coarse, wrinkled and protuberant, and its lumen adsorbed more debris and red blood cells; however, these phenomena were almost disappeared when these animals were treated with T. vulgaris. Similarly, the electron microscopic examinations showed a remarkable increase in aortic extracellular matrix with dispersion of their cell nuclei in hypertensive-untreated rats but not in rats treated with T. vulgaris. Therapy with T. vulgaris also reduced hypertension-induced aortic smooth muscle cell mass hypertrophy and normalized both aortic lumen diameter and media thickness. In conclusion, our results indicate that hypertension induced in rats was associated with injury of aortic tissue that may accelerate the arterial dysfunction in uncontrolled hypertensive conditions. More importantly, supplementation with T. vulgaris as herbal remedy has shown remarkable antihypertensive effect and marked improvement on hypertension-related biochemical changes and aortic vascular damage in rats.

Key words: Aorta, hypertensive, thymus vulgaris, rat.