Implication of vitamin a deficiency on vascular injury related to inflammation and oxidative stress: effects on the ultrastructure of rat aorta

Abstract

Background: Vitamin A deficiency induces activation of NF-kB and impairs activities of antioxidant enzymes in aorta. Aim of the study: We study the effect of vitamin A deficiency on the aorta histoarchitecture and the possibly contribution of its prooxidant and inflammatory effects to artery alterations. Methods: Twenty-one-day-old Wistar male rats were fed during 3 months with vitamin A-deficient diet (−A, n = 8) or the same diet containing 8 mg of retinol palmitate/kg of diet (+A, control, n = 8). In aortas, thiobarbituric reactive substances and reduced glutathione levels were measured by spectrophotometry. Expressions of TNF-alpha, NOX-2, VCAM-1, and TGF-beta1 were assessed by RT–PCR and Western Blot. The morphology of aorta was examined by light and transmission electron microscopy. Results: In −A rats, high levels of TBARS in serum and aorta and low levels of GSH in aorta were found. An increased expression of TNF-alpha, NOX-2, VCAM-1, and TGF-beta1 in aorta from −A rats was observed. Examination of the intimal layer by light microscopy indicated the presence of an irregular surface in −A aortas. TEM studies showed large vacuoles and multivesicular bodies along the endothelium and also multivesicular bodies in the subendothelial space of aortas from −A rats. Furthermore, the histological appearance of internal elastic lamina was different from control. Small vesicles in the medial layer were observed in aortas from vitamin A-deficient rats. Conclusions: Vitamin A deficiency produces histoarchitectural alterations in aorta, which can be associated, at least in part, to the oxidative stress and inflammation induced by vitamin A deficiency.