The experimental study of losartan's protective effect on cardiac and arterial aging

Objective By observing degree of myocardial fibrosis, changes of vascular endothelium dependent relaxation dysfunction of elderly rats and losartan's intervention effect, to explore the protective effect of angiotensin II receptor I antagonist on cardiac and arterial aging. Methods 30 Wistar rats were averagely divided into the young group (3~4 months old), the old group (18~20 months old) and losartan group (18~20 months old, given losartan 20 mg·kg~-1 ·d~-1 for 8 w), the indexes of myocardial fibrosis, TGF-β1 expression, NO production and NOS activity of aorta were determined by biochemical method, immunohistochemistry, nitrate reductase and colorimetry respectively. Results Comparing to those in the young group, degree of myocardial fibrosis and TGF-β1 expression increased, vascular endothelium dependent relaxation reaction induced by acetylcholine were damaged (P0.05), NO production and total NOS activity also significantly decreased in the old group (P0.01). Comparing to those in the old group, degree of myocardial fibrosis and TGF-β1 expression decreased, vascular endothelium dependent relaxation reaction significantly increased (P0.01), NO production and total NOS activity all increased in the losartan group (P0.05). Conclusions With aging, the degree of myocardial fibrosis and TGF-β1 expression increased, vascular endothelium dependent relaxation function gradually decreased. Losartan could not only inhibit the degree of myocardial fibrosis in elderly rats, but also improve vascular endothelium dysfunction induced by aging.