Chronic administration of antioxidant resin from Virola oleifera attenuates atherogenesis in LDLr -/- mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Virola oleifera (Schott) A. C. Smith, Myristicaceae has been largely used in traditional folk medicine in Brazil as an anti-inflammatory agent and our previous data indicated the antioxidant properties in other oxidative stress-related models. However, its effects on atherosclerosis (AT) are not yet investigated.

AIMS OF THE STUDY: To evaluate the influence of resin from Virola oleifera (RV) on progression of AT in LDLr-/- mice.

MATERIALS AND METHODS: LDLr-/- mice were divided into 4 groups: 1) The ND group received a normal diet without treatment. 2) The HD group received a high-fat diet without treatment. 3) The HD-V50 received a high-fat diet and was orally treated with RV at 50mg/Kg. 4) The HD-V300 received a high-fat diet and was orally treated with RV at 300mg/Kg. After 4 weeks, blood was collected to quantify biochemical parameters and ROS total and the aorta was removed to measure the lipid deposition by en face analysis. The liver was also collected to determine total lipids and lipid and protein oxidation. In order to investigate in more detail the contributions of RV in the vascular structure, we carried out the in vitro tests using four cellular types: macrophages, fibroblasts, vascular smooth muscle and endothelial cells.

RESULTS: We showed that the chronic treatment of RV at both doses reduced vascular lipid accumulation (~50%, p<0.05), probably through systemic and hepatic antioxidant effects, independent of dyslipidemia. Moreover, the in vitro assay results demonstrated that RV develops antioxidant properties on the vascular smooth muscle and endothelial cells, reinforcing the protective role of RV in progression of AT. LPS-stimulated macrophages treated with RV resulted in a significant reduction of NO production in a concentration-dependent manner.

CONCLUSIONS: Chronic treatment with RV diminishes lipid deposition in atherosclerotic mice, which may be justified, at least in part, by antioxidant systemic and local mechanisms, reinforcing the protective role this resin in the setting of vascular lipid deposition, independent of hypercholesterolemia.