Valsartan decreases neointimal hyperplasia in balloon-injured rat aortic arteries by upregulating HO-1 and inhibiting angiotensin II type 1 receptor.

Aims Upregulation of heme oxygenase (HO)-1 plays an important role in vascular protection. Valsartan attenuates neointimal hyperplasia in animal studies. The objective of this study was to examine the role of HO-1 and angiotensin II type 1 (AT 1 ) receptor in the action of valsartan on neointimal hyperplasia in balloon-injured rat aortic arteries. Main methods Thirty-six male Wistar rats were randomly divided into the following three groups with twelve rats in each group: control group, surgery (model) group, and valsartan group. Aortic balloon injury was performed to elicit endothelial denudation with a 2F balloon catheter. On days 14 and 28 after injury, blood was harvested to measure bilirubin levels. Aortic arteries were harvested for morphometry analysis, to determine angiotensin II (Ang II) level, and to analyze mRNA or protein expression. Key findings Compared with the control group, proliferation and intimal thickening of vascular smooth muscle cells (VSMCs) were obvious in the surgery group rats on days 14 and 28 after injury. Valsartan significantly reduced the proliferation and intimal thickening. Additionally, pretreatment with valsartan significantly reduced Ang II levels, AT 1 receptor, and p38 mitogen-activated protein kinase (MAPK) expression. Valsartan increased HO-1 protein and mRNA expression, as well as increased serum bilirubin levels compared with the surgery group. Significance Valsartan treatment decreased neointimal hyperplasia in balloon-injured rats. The mechanism of action might be linked to the upregulation of HO-1, downregulation of AT 1 receptor and inhibition of p38MAPK signal pathway. [ABSTRACT FROM AUTHOR]