Antihypertensive potential and mechanism of action of astaxanthin: III. Antioxidant and histopathological effects in spontaneously hypertensive rats

We investigated the effects of a dietary astaxanthin (ASX-O) on oxidative parameters in spontaneously bypertensive rats (SHR), by determination of the level of nitric oxide (NO) end products nitrite/nitrate (NG(2)(-)/NO3-) and lipid peroxidation in ASX-0-treated SHR. Oral administration of the ASX-O significantly reduced the plasma level of NO(2)(-)fNO(3)(-) compared to the control vehicle (p < 0.05). The lipid peroxidation level, however, was reduced in both ASX-O- and olive oil-treated groups. We also analyzed the post-treatment effects of ASX-O on the vascular tissues by examining the changes in the aorta and coronary arteries and arterioles. The dietary ASX-O showed significant reduction in the elastin bands in the rat aorta (p < 0.05). It also significantly decreased the [wall : lumen] aerial ratio of the coronary arteries. These results suggest that ASX-O can modulate the oxidative condition and may improve vascular elastin and arterial wall thickness in hypertension.